Formulation of Chia Seed Cookie

CHAPTER 1

INTRODUCTION

Background

The seeds of the species Salvia hispanica L. is commonly known as chia and it is an important staple food, oil source and medicine for Mesoamericans in pre-Columbian times (Reyes-Caudillo et al., 2008). Salvia hispanica L. is named by Carolus Linnaeus (1707-1778) who discover that chia growing wild in the new world and confused it with a native plant from Spain (Valdivia-Lopez & Tecante, 2015). In actual, chia is an annual herb which is native to Mexico and Northern Guatemala, and it will bloom during the summer season (Ixtaina, et al., 2008). It is a biannually cultivated plant which prominently grown for its seeds, classifying under the mint family (Labiatae), super division of Spermatophyta, and kingdom of Plantae (Shah et al., 2014).  In Latin America, chia has very special significance, mainly because it has been consumed by Mesoamerican people since ancient times (Valdivia-Lopez & Tecante, 2015). Chia seed has been widely used for different application such as breakfast cereals, bars, cookie snacks, fruit juices, cake, and yoghourt by many countries around the world which includes United States, Canada, Chile, Australia, New Zealand, and Mexico (Norlaily et al., 2012). It has been used to make drinks and chia flour which is in powder form is used in various ways of food preparation (Borneo et al., 2010).

Recent studies explained the reason why ancient civilizations included chia as a basic component in their diet. Numerous studies have been carried out and shown the remarkable nutritional properties of the chia seed as it is recommended for consumption due to its high oil content, protein, antioxidants, minerals and dietary fibre (Ixtaina et al., 2008). The chemical composition and the nutritional value of the seed which is beneficial to human health have been leading it for commercialization. Chia seed offers huge potential in food industries, medical field, animal feed, cosmetics, pharmaceuticals and so on (Munoz et al., 2013).

According to Peiretti & Gai (2008), the evaluation of the chia seeds’ properties and possible uses have shown that it consists of very high nutritional value, with high contents of linolenic acid, dietary fibre, and protein. Besides, due to the presence of different bioactive compounds, chia seeds are being promoted as an important ingredient for functional foods, for instance, chia may be promising new source of antioxidants due to the presence of polyphenols (Reyes-Caudillo et al., 2008). Additionally, it is the source that contains high levels of polyunsaturated fatty acids (PUFA) which comprises of two main types, omega-3 fatty acid and omega-6 fatty acid. Improving the dietary intake ratio via increasing the consumption of omega-3 fatty acid is essential for brain functioning as well as for the management of cardiovascular disease, arthritis and cancer (Capitani et al., 2012). In addition, the intake of total dietary fibre which brings health benefits such as reduction of cholesterolaemia and modification of the glycemic and insulinaemia responses, making total dietary fibre become an important component in the daily diet (Shah et al., 2014). Therefore, it is important to increase the daily intake of dietary fibre in order to maintain digestive health.

Cereal-based products play an important function in human nutrition. Bakery products such as cookies and cakes are the most traditional transformation products in which cereals have been used as an ingredient as it is considered as an excellent source of energy and other major nutrients as well (Barrientos et al., 2012). The bakery products have been enhanced from day to day in order to increase the nutritional value by mean of supplementation with different types of materials such as proteins, minerals, and fibre. The trend of consuming snack food has been increased due to the reason of urbanization and increase in the number of working women (Dayakar Rao et al., 2016). Food-based industry is exploiting this development by fabricating nutritious snack foods and thus becoming one of the popular bakery items consumed nearly by all levels of society (Sudha et al., 2007). Cookie hold an important position in snack food industry, mainly due to its convenient nature, good nutritional quality, reasonable cost, longer shelf-life and varieties in terms of taste, crispiness and digestibility (Sudha et al., 2007). Besides, cookie can be manufactured in a large amount of quantities with minimum time requirement and enable widespread distribution (Zucco et al., 2011).

The development and production of new products to be commercially marketed are a strategic area of the food industries. Foods that are produced nowadays are not solely intended to supply basic nutrients but also mean to enhance the physical and mental health of consumer as well as prevention of nutrition-based diseases (Menrad, 2003). There are two major properties which are demanded by the consumers for the food products in which the first-one is dealing with the traditional nutritional aspects of the food while the second features refer to the additional health benefits compared to its regular consumption (Shah et al., 2014). These types of food products are usually named as functional foods, which are targeted around the world due to the wave of healthy lifestyle changes caused by the rising awareness and interest of consumer in health (Shah et al., 2014). Functional foods are gaining prominence across the globe. The purpose of functional food consumption is to improve the health of the community by becoming part of daily diet of consumer (Kaur & Singh, 2017).

Wheat is a cereal grain grown around the world due to its highly nutritious and useful gain (Agu & Okoli, 2014). It is one of the major world agricultural products with total global production of about 600-700 million tons (Shewry et al., 2012). Wheat can be cultivated easily with high yielding because it is well adapted to the environmental and the condition of the soil that occurs throughout the temperate region of the world (Hui, 2008). It is an important staple food and acts as the basic ingredients in bakery production such as cookie. Wheat is classified into classes suitable for the major end uses such as baking, noodles, and animal feed, which mainly based on the texture of wheat and on the quality content of the grain protein (Shewry et al., 2012). Wheat is normally divided into two texture classes, which are hard and soft based on the suitability for baking. Hard wheat has a physically hard kernel which yields high gluten and consequently high protein content whereas soft wheat is characterized by a lower protein content (Mushet, 2008).

Problem Statement

Chia seed is rich in functional ingredients and high in nutrients; however, its consumption value is limited as only minority within the community are consuming chia seed. Their limited consumption by the population is partly due to the scarce information regarding its nutritional benefits as processed food. In addition, chia seed is an ingredient which has not yet been fully utilized to its maximum potential in food industries. The incorporation of chia seed into food is not prominent in Asian countries such as Malaysia. The availability of chia seed on the market is limited as chia seed is normally sold in the upscale shop which requires purchasing ability, thus reducing the accessibility of public towards it.

Justification of Study

The development of underutilized chia seed products is very economically important in order to introduce this highly nutritious food to the world. As chia seed is highly nutritious and contains various types of phytochemicals, it has become new generation of “superfood”. Besides, it is important to introduce a new way of consuming chia seed to the populations in order to encourage the consumption of chia seed. For vegetarians, chia seed can be a very good source of omega-3 content which normally obtain from salmon fish. The shortage of low-cost products with high nutritional value has also gathered researchers to seek for the best formulation of chia seed products with reasonable price so that it is affordable by everyone. Considering that not much research has been done on the cookie with added chia seed, thus, development of chia seed cookie is chosen in this study because cookie is commonly consumed by people at all ages around the world and to encourage the consumption of chia seed which has high nutritional values and health benefits.

Hypothesis

The incorporation of chia seed into cookie has significant effect on the nutritional value, physical and sensory quality of cookie.

Objectives

1. To determine the best formulation of chia seed cookie based on the sensory assessment.
2. To determine the proximate composition of the chia seed cookie.
3. To determine the shelf life of the chia seed cookie.

CHAPTER 2

LITERATURE REVIEW

Chia Seed

Chia (Salvia hispanica L.) is a native herbaceous plant of southern Mexico and northern Guatemala which have been cultivated semi-annually (Munoz et al., 2012). It is an oilseed plant used as a foodstuff due to being a natural source of many nutrients. The leaves of chia plant are known to have a high-potential commercial interest due to its nutritional composition. However, the seeds are the most attractive part basically for the content of protein, fibre, antioxidants, and oil (Valdivia-Lopez & Tecante, 2015).

Chia plant is very sensitive to day light and produces black and white colour seeds (Ixtaina et al., 2008). The size of chia seed is very small, which is 1.87 ± 0.1 mm length, 1.21 ± 0.08 mm width and 0.88 ± 0.04 mm thickness with an oval flattened shape and ranged in colour from dark coffee to beige with small darker spots as shown in Figure 2.1 (Munoz et al., 2012). The black and white coloured seeds are slightly different from each other. The white seeds are usually greater in weight, width and thickness as compared to the darker ones (Ixtaina et al., 2008). Besides, according to Suri, et al. (2016), the average moisture content of black seed is higher compared to the white colour one whereas the oil yield of white seed is higher than black seed.

The seed consists of three main parts, which include the coat, the embryo and the endosperm (Valdivia-Lopez & Tecante, 2015). The testa or coats will act as a protecting layer in the embryo. When the seed is made contact with water, the coat which contains the mucilage which is a polysaccharide substance will then start swelling, forming a sticky and gelatinous capsule around the seed and strongly adhered to it (Valdivia-Lopez & Tecante, 2015). The seeds are usually very stable to storage condition due to the reason that it is not highly hygroscopic. This can be shown by isothermal adsorption data over the relative humidity of 7-91% and the temperature ranges from 20-65 °C (Moreira et al., 2012). Cultivation and domestication will cause changes in qualitative characteristics of the chia seed in terms of the colour of the seed covering, stem pigmentation, and shattering (Valdivia-Lopez & Tecante, 2015).

Figure 2.1Salvia hispanica, seed. Dark chia seed (left side). White chia seed (right side)

Source: Munoz et al. (2012)

Nutritional Composition of Chia Seed

Chia is a plant which is rich in nutrient content. It is considered to be of nutritional significance in terms of the fatty acid composition, fibre and protein content as well (Suri et al., 2016). The nutritional values of chia seed are shown in table 2.1

Table 2.1 Nutritional values of chia seeds (per 100 g)

Source: USDA (2017)

Chia seed is rich in total dietary fibre, which is needed by human in the daily diet. According to the Dietary Reference Intakes, the recommendation for adult dietary intakes is in the range of 25-38 g per day (American Dietetic Association, 2008). The total dietary fibre contents of chia seeds are ranges from 34 to 40 g per every consumption of 100 g, equivalent to 100% of the daily recommendation for the adult population (Munoz et al., 2013). The dietary fibre is much higher than that present in several grains, vegetables and fruits, which includes corns, carrot, spinach, banana, pear, apple, and kiwi (Reyes-Caudillo et al., 2008; Ovando, et al., 2009).  Dietary fibre can be categorized into insoluble fibre that will exhibits bulking action and soluble fibre which will ferment either partially or completely in the colon (Anderson et al., 2009).

Chia seed has higher level of protein content compared to most of the traditionally utilized grains; they contain approximately 19−23% (w/w), which is higher than that of wheat (14%, w/w), corn (14%, w/w), rice (8.5%, w/w), oats (15.3%, w/w), and barley (9.2%, w/w) (Sandoval-Oliveros and Paredes-López, 2013). The amino acid content of protein which obtained from chia is more complete than the protein obtained from other grains (Valdivia-Lopez & Tecante, 2015). The essential amino acids such as leucine, isoleucine and valine comprise 42.2-42.9% of the total amino acids presence in chia seeds (Olivos-Lugo et al, 2010).

According to Olivos-Lugo et al. (2010), oil content in chia seed is higher compared to common oil seed such as soya bean and cotton seed, indicating that chia seed is an important source of oil. One of the most prominent characteristics of chia seed is that it has high content of polyunsaturated fatty acid (Jamboonsri et al., 2012; Martinez et al., 2012). Chia seed contains a significant amount of omega-3 unsaturated fatty acid, which is considered as an essential fatty acid because it cannot be synthesized by the human body (Valdivia-Lopez & Tecante, 2015). Besides, chia is known to be an excellent source of minerals as chia seed contains six times more calcium, eleven times more phosphorus and four times more potassium than 100 g of milk, besides containing magnesium, iron and zinc (Munoz et al., 2013). In addition to being nutritionally important for good health, chia seed also acts as a good source of vitamins such as the niacin content in chia seed which is higher compared with other cereals such as corn, soybeans and rice (Munoz et al., 2013).

Health Benefits of Chia Seed

Chia seed is known as one of the ‘super food’ because it provides high doses of antioxidants, polyphenols, vitamin and minerals to human nutrition. It is considered as functional food as it beneficially affects cardiovascular diseases, inflammatory and nervous system disorders, intestinal transit regulation and blood cholesterol and triglyceride levels (Munoz, et al., 2013). According to Vuksan et al. (2010), medical studies show that consumption of 37 g/ day of the oily seed S. hispanica has a positive effect on cardiovascular risk factors by reducing the blood pressure and inflammatory.

Fibre is one of the important components in a healthy diet. Population should consume dietary fibre in an adequate amount from various plant foods as recommended by the American Dietetic Association (2008). According to Reyes-Caudillo et al. (2008), chia seeds have a high content of fibre. Sufficient intake of the amount of dietary fibre is related to the prevention of cardiovascular diseases, which includes stroke, myocardial infraction, vascular diseases, obesity, hypertension, hyperglycemia, and hyperlipidemia (Suri et al., 2016). The intake of dietary fibre has been linked with the increase of post-meal satiety and reduces the chance of subsequent hunger. Chia seed aids in the loss of body weight without starving due to the unique gelling action of the chia seed which can keep the consumer feeling full for hours. This is because it has hydrophilic properties, being attracted to water due to the microfibres in the outer coating of the seeds which allow it to absorb more water. Chia seed will form a coating of gel when it is exposed to water, and this will increase the size and weight on the stomach, giving satisfying effect. The feeling of fullness will reduce the rate of digestion, thus, leading to a stable increment of the blood sugar levels and a stable release of the insulin in the body (Munoz et al., 2013). Vuskan et al. (2007) carried out a research study, in which 20 healthy diabetic patients were given chia bread and additional of whole chia seed to be sprinkled on food daily at home. Based on the result of the study, it was suggested that diabetes can be controlled with the consumption of high-fibre diet.

Chia seeds exist in different colours, which ranged from black to white, having minor difference in their nutritional properties. For example, black seed is known to have higher concentration of antioxidant and fibre whereas, white seeds contain slightly more protein instead of fibre. Recent studies have shown that chia seeds are rich in antioxidants, which are useful in inhibiting the oxidation process in the body’s cell by donating free radicals to the reactive oxygen species (Valdivia-Lopez & Tecante, 2015). Chia seed contains a significant amount of primary and synergistic natural antioxidants, which include chlorogenic acid, caffeic acid, myricetin, quercetin and kaempferol. Oxidation on body’s cell is a chemical reaction which will produce free radicals that might lead to destruction of cell within human body. According to Marineli et al. (2015), the antioxidant is used in reducing the reactive oxygen species which usually leads to damage of cell protein, lipids and DNA, which might result in loss of function and even cellular death. The phenolic compounds which act as an antioxidant are found in the chia seed which may reduce the invasiveness cancer cell and improve the clinical outcomes (Valdivia-Lopez & Tecante, 2015). Antioxidant can protect consumers from diseases and promote beneficial health effect because antioxidant activity can prevent chain initiation, binding of transition metal ion catalysts, decomposition of peroxides, prevention of continued hydrogen abstraction and radical scavenging protecting against oxidative damage to DNA, proteins and lipids (Marineli et al., 2014).

Chia seed contains significantly higher nutrients compared with other crops (Valdivia-Lopez & Tecante, 2015). However, chia seed does serve mainly for omega-3 fatty acid. Chia seeds are consumed by people in many countries in order to maintain healthy serum lipid levels of the human body due to the presence of phenolic acids and omega-3 and omega-6 oil. The omega-3 unsaturated fatty acid is important and helpful in order to prevent and management of hyperlipidemia, hyperglycemia and hypertension (Capitani et al., 2012). It can be classified into α-linolenic fatty acid, eicosapentaenoic acid, and docosahexaenoic acid. The percentage of α-linolenic fatty acid in chia seed is known to be highest compared to any other plant source (Ayerza & Coates, 2011). The high proportion of the essential α-linolenic acid which contains in the chia seed is linked to certain physiological functions (Chicco et al., 2009). According to Brenna et al. (2009), α-linolenic fatty acid act as a precursor of polyunsaturated fatty acid and supplementation of diet with high levels of α-linolenic fatty acid will lead to small but significant increases in eicosapentaenoic acid, and docosahexaenoic acid. Besides, chia seed has become an alternative omega-3 fatty acid source for vegetarian and people who are allergic to fish and fish products. Majority have a perception that seafood is the optimal dietary source of omega-3 fatty acids; however, chia seed contains nine times the amount found in salmon (Preedy et al., 2011).

Functional Properties of Chia Seed

According to Olivos-Lugo et al. (2010), chia seeds are high in dietary fibre (34.6%), protein (24.6%), and oil contents (32.2%). The high dietary fibre content of the seed has an implication on its functional characteristics in food. Fibre can be classified as soluble dietary fibre and insoluble dietary fibre. The example of soluble fibre is viscous or fermentable fibre, which will be fermented in the colon, whereas insoluble fibre is having bulking action with a limited extent of fermentation in the colon (Anderson et al., 2009). The additions of fibre-based ingredients such as chia into the food products are able to improve the sensory perception. The functional properties of chia gel which is rich in dietary fibre have a great potential in food application by acting as a thickening agent, emulsifying agent and stabilizer. The extracted chia gel has good water-holding capacity, oil-holding capacity, emulsion activity (Coorey et al., 2014).

Water-holding capacity is defined as the amount of water which can be absorbed and held by the hydrated sample after an external force is being applied (Olivos-Lugo et al., 2010). The factors which will impact water-holding capacity include the ingredients and water interaction, number of hydration positions and protein configuration (Galla & Dubasi, 2010). Chia seed gel has higher water-holding capacity due to the presence of high protein and fibre contents as these components could bind with water molecules (Coorey et al., 2014). According to Olivos-Lugo et al. (2010), good water-holding capacity is necessary in manufacture of certain food products such because it can improve the structure and decrease the amount of water loss during cooking. Chia seed exhibits excellent water-holding capacity due to the mucilage in chia seed, which acts as soluble dietary fibre (Capitani et al., 2012). The mucilage appeared as a transparent ‘capsule’ which surrounds the seed when chia seed came into contact with water. In addition, Munoz et al. (2012) demonstrated the extraction and hydration of chia mucilage, which has great water-holding capacity because 100 mg of mucilage sample was able to absorb 2.7g of water, which is 27 times its own weight. Chia seeds and its mucilage which has high water-holding capacity can be used as thickener in food (Inglett et al., 2013).

Oil-holding capacity is the absorption of oil occurs via the lateral nonpolar sites within the protein molecules (Olivos-Lugo et al., 2010). Chia seed gel is having higher oil-holding capacity because of the concentrated sponge-like nature in which there is a greater space in it spongy structure to absorb and trap the oil (Coorey et al., 2014).  Chia seed can be blended into a form of powder, which is known as chia flour. The oil-holding capacity of chia flour gel is lower compared to chia seed gel because the sponge-like structure of chia flour gel contained chia flour particles, disrupting the oil-holding capacity within the pores of the spongy structure (Coorey et al., 2014).

Coorey, et al. (2014) reported that chia seed gel was having good emulsification activity and able to form stable emulsions. The emulsion activity is the measures of the ability of an emulsifying agent to form a water-in-oil dispersion whereas the stability of the emulsions is the measures of its breakdown over time. Furthermore, Alfredo et al. (2009) revealed that fibre-rich fraction of chia has an emulsifying activity of 53.26%, and the emulsion stability was 94.84%. It is claimed as a good emulsifying agent where it can be used in foods requiring emulsion formation and ones with long shelf life. Also, its good emulsifying properties was due to the ability to form a viscous continuous phase in water-emulsion phase and high oil-holding capacity (Coorey et al., 2014). The addition of chia seed which is rich in dietary fibre will affect the food texture as it contributes to the stabilization of food structure by providing a stable emulsion through gel formation and thickening of the continuous phase (Capitani et al., 2012).

Application of Chia Seed in Food Industry

During pre-Columbian times, chia seed was known to be an important staple food for Mesoamericans (Reyes-Caudillo et al., 2008). Nowadays, it is being consumed by people in many countries because of the nutrimental benefits. It is a fact that chia seed based formulation and supplements are gaining a place on the market nowadays due to the increasing preference of public who tries to maintain a healthy diet from the known properties of the compound which is present in chia seed (Valdivia-Lopez & Tecante, 2015). Chia seed is used for different purposes in different countries. In 2009, chia seed was approved as a novel food by the European Parliament and Council of Europe (Munoz et al., 2013).

Bakery Products

Shah et al. (2014) have studied on the effect of replacing wheat flour by chia seed flour on the nutritional and sensory attributes of the cookie. Based on the evaluation of the results, it was found that whole chia seed flour can be used to fully replace the wheat flour in order to produce gluten-free cookie. The result has shown that the nutritional and functional properties of cookie can be improved by utilized whole chia seed flour to substitute wheat flour. In the study, Shah et al. (2014) reported that the ash content increases due to the high percentage of mineral content present in chia flour. Besides, the content of protein, fat and dietary fibre in chia seed cookie also higher compared to the cookie solely made by wheat flour. However, there is one disadvantage as the cookie made by using chia seed flour will give a slightly blackish or brownish colour. The colour of cookie will become increasingly dark by using high proportion of chia seed flour.

Pizarro et al. (2013) utilized whole chia flour to pound cake and compared it with a standard cake. They revealed that the level of omega-3 were significantly increased at 15 g of whole chia seed flour/ 100 g of flour mixture. The cake produced which included whole chia flour showed good sensory acceptance in overall; however, it presented slightly lower scores in terms of flavour and taste compared to the control cake. Besides, Rendon-Villalobos et al. (2012) also prepared tortillas with added chia and they reported that the sensory property of the tortillas was not affected by the addition of the chia seed, but it increases the nutritional value of the product.

Overweight issues have increased recent years and linked to many non-communicable diseases. Thus, the recommendation of fat reduction is encouraged in many food products which may contribute to reduce the risk of overweight. Felisberto et al. (2015) investigated the effects of the replacement of different percentage of vegetable fat by chia mucilage gel on the technological properties of pound cakes. They found that the replacement of vegetable fat by CMG did not significantly alter the specific volume, symmetry, uniformity, moisture and water activity of the cakes. However, the colour and firmness of cakes were influenced by higher levels of fat replacements with chia mucilage gel. Thus, they concluded that the replacement of up to 25 g/ 100g of fat by chia mucilage gel is technologically feasible. Also, Borneo et al. (2010) had successfully replaced oil and eggs with chia gel in a cake formulation. Together with his teammates, Borneo reported that the functional properties and sensory characteristic of the cakes was maintained and accepted by consumers with substitution of chia gel up to a level of 25%. There is an improvement to the quality regarding the fat profile in the cakes observed in which the eggs or oil is replaced by chia gel. The study shows that the ratio of omega-3, and omega-6 fatty acid improved as the substitution increased. Besides, the cholesterol content decreased as egg were substituted by chia gel.

Drinks and Beverages

Drinks made with chia seed has attained great popularity among people. Chia seeds are soaked in water or fruit juice and are consumed as refreshing drinks (Inglett et al., 2013). Besides, a Mexican drink prepared by mixture of water and lemon juice with soaked chia seed in it is known as ‘agua de chia’ or ‘chia fresca’. This drink preparation is a good source of protein in which the protein content and amino acid content is higher compared to most traditional utilized grains (Monroy-Torres et al., 2008).

Morato et al. (2015), reported that by consuming the formulation of a functional chocolate milk which is added with omega-3 rich chia oil is an alternative to decrease post-exercise soreness of muscle since it was able to reduce markers of muscle damage and improved the blood lipid profile. The reduce in muscle damage is caused by an improvement of the antioxidant system as the ingestion of omega-3 enriched chocolate milk increased the enzymatic activity of the antioxidant defences. Besides, there is a significant improvement on the triacylglycerol level and the markers of immune function. Morato et al. (2015) concluded that macronutrient present in the omega-3 which enriched chocolate milk was linked to positive physiological and biochemical effect, making it a potentially functional beverage suitable for physically active individuals.

Oils and Supplements

Chia seed is valued for its oil, and it has been processed into the healthy oil supplements for humans and animals (Norlaily et al., 2012). Chia seed contains a large quantity of essential oils, and the main supplication of it is in the production of capsules, which provide the consumer with a nutritional supplement of omega-3. Besides of oil supplement, chia seed oil is being used as cooking oil. The fatty acid composition of chia seed oil may be appealing for healthy food since it consists of large amount of polyunsaturated fatty acids (Ixtaina et al., 2010). The chia oil can be extracted from the chia leaves where it can be consumed as a condiment or used as a fragrance (Munoz et al., 2013). Due to the presence of tocopherol, phytosterols, carotenoids and phenolic compound, chia seed oil is considered as a new source of natural antioxidant, which has the ability to protect consumers from diseases and promote a beneficial effect on health (Alvarez-Chavez et al., 2008).

Cookie

The term cookie is called all around the world, referring to a baked product generally consists of three major ingredients, which are flour, sugar and fat (Pareyt & Delcour, 2008). Cookie is widely consumed around the world with their properties of eating convenience and long shelf life (Agama-Acevedo et al., 2012). The constituents of the cookie dough will definitely influence dough making and handling, cookie baking and the quality of the resulting product (Pareyt & Delcour, 2008).

Cookie is a convenient snack due to its ready-to-eat (RTE) nature. Cookie is a small, flat and baked food product, which usually made up of the major ingredients with the adding of baking agents, flavorings and so on. It can be made in a wide variety of styles by using different ingredients in order to meet the demand of the consumers. Continuous development of cookie with different formulation has been done to introduce into the market. Barrientos et al. (2012) produced cookie which is supplemented with chia flour contained significantly higher level of proteins, fat, crude fibre, calcium, zinc, and α-linolenic acid. The addition of chia flour to the cookie produces products which received high sensory acceptance with a better fatty acid profile. Seker et al. (2008) reported that substitutions of fat content with apricot kernel flour in the cookie was acceptable to the panellists, and the cookie was proved to have a significant increase of the total dietary fibre compared to the control cookie.

Kaur et al. (2017) produced cookie with the replacement of wheat flour with varying levels of flaxseed flour. Cookie produced from composite flour mixes was significantly higher in nutrient contents which are protein, fat, ash and fibre in comparison with the control sample. He found that flaxseed is rich in antioxidant potential due to higher total phenolic content and free radical scavenging activity of composite flour cookie as compared with the control ones. According to Ganorkar & Jain (2014), cookie incorporated by flaxseed flour has higher nutrient content in which the amount of α-linolenic acid was increased, and the fibre content was nine times more in flaxseed flour cookie compared with the control.

Cookie Ingredients and Their Functions

There are few primary functional ingredients used to make cookie, which are wheat flour, sugar, margarine, baking soda, salt and water.

Wheat Flour

Flour is the fine powder which is derived from the endosperm portion of cereal seeds or other starchy foods. It is the major ingredients used to produce bakery products such as biscuits and cookies. The function of flour is to provide the structure, texture, and flavour to baked products (Hui, 2008). The most common source of flour is wheat; however, other cereal grain such as oat, rye, barley, rice, corn and others can also be used to produce flour. Flour can also be made from non-cereal sources such as soybeans, potatoes, taro and other starchy foods.

Wheat is one of the major food sources for people in 43 different countries, which account for 35% of the total world population which used to consume wheat-based food product (Zhang et al., 2013). According to Ronda & Roos (2011), wheat is being ranked in the second place right after rice as the main human crop. The composition of wheat has become the main reason which makes wheat as the leading food source in the world. The protein content of wheat is higher compared with other cereal food products such as maize and rice, making wheat as the leading source of cereal protein for human nutrition (Bhat et al., 2016)

Wheat flour is normally used as the principal component of cookie because it will form a unique visco-elastic dough when mixing with water due to the formation of gluten (Sudha et al., 2007). It is the most versatile cereal due to its capacity of its storage proteins to interact with each other followed by developing the gluten network (Hui, 2008). This elastic gluten framework stretch to contain the expanding leavening gases, which contributes to the ability of the dough to rise and maintain its shape (Hui, 2008). There are two basic categories of wheat, which are hard wheat and soft wheat. Hard wheat contains higher protein content, and it is often labelled as bread flour which used for baked goods that need a strong and flexible structure whereas soft wheat has less protein content and more starch which is ideal for baked goods, which are not kneaded such as cookies and pancakes (Mushet, 2008). Wheat flour is a binding agent which considered as the backbone and responsible to form the structure of the cookie and most importantly, it holds and distributes all other ingredients together uniformly into the cookie dough (Ashokkumar, 2009).

Brown Sugar

Sugar is a disaccharide made up of one molecule of glucose and one molecule of fructose. It is a non-reducing sugar that has a higher degree of stability, which allows it to be cooked at a high temperature without breaking down or undergoing browning reactions. Sucrose is the most commonly used sweetener in baked goods. It is crucial in cookie making because it delivers sweetness, affects the structural and textural properties. Besides, it is presumed to incorporate air into fat during the preparation of the cookie dough (Pareyt et al., 2008). The dough and the product properties are determined by sugars and other types of sweeteners. The impact of sugar on cookie dough spread can be explained as during baking, additional sucrose-water solvent phase can be yield due to the progressive dissolution of sucrose. Higher sucrose level will increase the spread rate, leading to a larger final cookie diameter (Pareyt et al., 2009).

Sugar also performs additional function in baking, which includes tenderizing, adding moisture and leavening (Mushet, 2008). Normally, white granulated sugar will be used in baking; however, brown sugar can also be considered as an option in baking. The definition of brown sugar is ‘soft sugar’ or pure white sugar crystals, which are covered by a film of molasses syrups or golden coloured syrup. Brown sugar acts in a different way in cookie compared to white sugar due to its ability in bringing an extra layer of flavour (Mushet, 2008). The amount of molasses added to the granulated sugar will determine whether the sugar will be light brown or dark brown and the darker the colour of the brown sugar the stronger the flavour of molasses. Thus, the sugar has effects on the products’ colour due to the presence of molasses where high amount of molasses will contribute to a darker colour cookie (Mushet, 2008). The nutritional values of both white sugar and brown sugar are shown in table 2.2. By comparison, brown sugar contains higher nutritional values in terms of mineral compared to refined white sugar.

Table 2.2 Comparison of nutritional value between white and brown sugar (per 100 g)

Source: USDA (2017)

Margarine

Margarine is plastic fat which contains a high proportion of fats and oils (Arifin et al., 2010). Fat is one of the very important ingredients in baking cookie since it will contribute texture and pleasing mouthfeel as well as a positive impact on flavour intensity and perception (Arifin et al., 2010). Margarine is produced by the main ingredients which consist of various hydrogenated animal and vegetable fats, flavouring ingredients, emulsifiers and colouring agents. It contains 80-85% fat, 10-15% moisture and about 5% salt, milk solids and other components as well (Hui, 2008). Margarine is a water-in-oil emulsion in which the fat crystals will keep separating the water droplets. It is used for baking cookie to impart a variety of beneficial properties to the cookie dough as well as to the finished cookie such as lubrication and aeration of the dough, aiding in flavour release and provides desirable texture and mouthfeel to the cookie (Cheong et al., 2009). It acts as a lubricant which contributes to the plasticity of the cookie and prevents excessive development of the gluten proteins during mixing (Jacob & Leelavathi, 2007).

Baking Soda

Baking soda is a type of chemical leavener which is activated by liquid or acidic ingredients such as buttermilk, lime juice and brown sugar (Mushet, 2008). It is used as a tenderizing agent because carbon dioxide is produced during baking process, which will leaven the cookie and provides a tender texture. Process of leavening occurs as gas is being produced when baking soda combined with acidic ingredients. The leavening of cookie is important to increase the total volume of the cookie and alters the width of the cookie in relation to its height, which is known as the spread ratio (Hui, 2008).

Salt

Salt is obtained from natural deposits and the sea which is usually purified and vacuum dried to a desired crystal size. Salt is known as one of the five basic tastes which has its own characteristics. It is being used in many cookie formulation due to its ability to enhance the flavour of the products. Besides of being just a seasoning or flavour enhancer, salt has the ability to strengthen gluten structure in order to make the baking products more stretchable. Gluten is able to hold more water and carbon dioxide in the presence of salt, in turns allow the dough to expand more while holding its structure (Gisslen, 2008). Furthermore, salt is acting as a preservative in which it can prolong the mould-free shelf-life of bakery products.

Water

Water plays an important role as a baking ingredient due to its overwhelming abundance. Water is being called as a catalyst in cookie making because it plays the role in making the dough formable or to change the character of the ingredients, however, it must be eliminated almost completely during the process of baking (Pareyt & Delcour, 2008). The amount of water controls the quality, texture, taste, odour, volume, flavour, and the mouthfeel of bakery products (Hui, 2008).  Water will provide lubrication to the consumers when the bakery product is being eaten, which will affect its texture (Hui, 2008). Besides, water plays an important role in terms of solubilisation of other ingredients, which includes sugar, salt, and various leavening chemicals, and it will aid in the dispersion of fat and other ingredients through the dough (Pareyt & Delcour, 2008).

Water will interact with many ingredients such as flour, which contain mostly starch and proteins. Starch is hydrophilic which will interact with water molecules; however, water molecules take time to get into starch granules due to its tightly packed structure. On the other hand, proteins are polymers which have hydrophilic groups but some of the protein contains hydrophobic segments. The chain of protein will mingle up when water is added into it, forming a sticky globule (Hui, 2008). Besides, sugars which added for fermentation and flavour is more soluble in water compared to starch. Furthermore, table salt and leavening agent such as baking soda or baking powder are electrolytes because they can form positive and negative ions, which can strongly attract polar water molecules (Hui, 2008).

Production of Cookie

Dough Mixing

Dough mixing is an important operation during the preparation of cookie. The objectives of dough mixing are to incorporate all ingredients uniformly, hydrate the flour together with other dry ingredients and to develop gluten (Hui, 2008). The characteristics of the cookie dough will be affected by the quality of the ingredients being used and the processing condition such as the mixing time and resting time. The dough mixing methods for cookie are very similar to the cake mixing methods. However, the main difference between both the preparation of cookie and cake dough is less water is usually used in mixing cookie dough. Less liquid is being used for the dough mixing process will lead to an easier mixing and less gluten development as well (Hui, 2008). Gluten is an important functional component presence in wheat, which contributes to the viscoelasticity of wheat flour dough. The structure of the gluten together with the interactions occurs within the protein complex will determine the dough properties (Wang et al., 2007).

There are three methods to prepare cookie dough such as one-stage, creaming, and sponge. One-stage method involves the mixing of ingredients all in one stage. It is straight-forward, but the maker will have less control over the mixing of ingredients (Hui, 2008). Creaming method is considered as the most common cookie-making method which involves the beating of the sugar with fat source such as margarine or butter until the texture become pale, creamy and fluffy. In this method, eggs will always be added into the mixture before the dry ingredients (Hui, 2008). Sponge method is seldom used in baking cookie. This method begins with the eggs being whisked together with the sugar. Dry ingredients will then be folded gently into the egg mixture, keeping the mixture light and foamy (Hui, 2008).

Baking Process

The baking process of a dough involves the transformation into a cellular solid with a characteristic final texture (Pareyt & Delcour, 2008). This process is caused by the expansion of the dough which subjected to the vaporization of water and gases from the leavening powders. The natural structures of the major dough constituents are altered irreversibly by a series of physical, chemical and biochemical interactions within baking process. According to Pareyt & Delcour (2008), the most important changes occur during baking process is the changes in dimensions due to the spread, loss of moisture, and development of colour and flavour. Several other phenomena will also happen due to the oven heat such as the expansion in volume, enveloping crust formation, inactivation of enzyme activities, coagulation of the flour protein as well as gelatinization of flour starch (Hui, 2008)

In baking process, portioning and panning of cookie have to be carried out because the size, shape and quantity of the dough will affect the baking time and temperature (Suas, 2009). In baking process, heat is transmitted to the baking products in three different way, which are radiation, convection and conduction. Oven heating is an important step in baking process because insufficient oven heat supply will cause the products to be baked under lower temperature and tend to extend the baking time whereas excessive oven heat will make the crust begin to turn into brown at the early stage baking, but the crumb of the products will still be gummy and lack of flavour at that moment. The invisible infrared rays will be emanated by the surface of the oven which is then absorbed by the exposed surface of the baking products. The dough surface will get warm more rapidly when it is exposed to heat of the oven compared to the interior part of the dough which is warmed progressively more slowly as the distance from the surface increases (Hui, 2008).

Different reactions will occur during the baking process. Caramelization and Maillard reactions are both reactions, which produce the brown pigments and contributes to the colour of the cookie during baking (Laguna et al., 2011). According to Hui (2008), caramelization involves the process where colourless and sweet substances, under the influence of heat, has transformed into compounds varying in colour from light yellow to dark brown and leads to a production of mild and pleasant caramel to burnt, bitter or acrid flavour. Maillard reaction is also considered the source of aromatic and flavour compounds that results from the heat application which contributes to the acceptability of cookie and other bakery products (Perez et al., 2012).

Cooling and Storage

Cookie is usually soft and susceptible to damage when they have been taken out from the oven. When the cookie is pulled from the oven, the centre part of the cookie still appeared slightly pale in colour; however, the paleness will disappear after five minutes because the cookie is still baking internally at the beginning. Thus, the cookie has to be cooled at the room temperature in order to allow it to set up. The cookie is allowed to cool on the pan which they are baked in until cool. In the cooling process, the cookie should not be stacked on each other when they are still warm because they might then stick together (Suas, 2009). An ample space is necessary to keep the cookies apart in order to promote the cooling process.

Storage is the last stages of cookie production, and it is crucial in terms of the purpose of protection. The time of period starts from the packaging of cookie to consumption is affected by the ways of storage. The flavour, taste and appearance of the cookie should be protected and remained as much as possible during this period of time. Cookie should be stored after it is completely cooled to prevent it from releasing steam in the container which may lead to spoilage. Cookie will be stored in the air-tight containers where each type of cookie is stored separately in different containers in order to prevent different cookies from absorbing flavour of each other, which will cause the cookie to taste all the same at the end (Baggett, 2012).

Study of Shelf Life

The shelf life of baked products is defined as the maximum time period in which the products can be maintained in terms of the sensory and physical characteristics which is related to the freshness of the products such as crumb tenderness, compressibility and moistness by avoiding alteration related with staling during the period of storage (Baixauli et al. 2007). The shelf life of a product is determined once there is significant change in overall acceptability if being detected (Gimenez et al., 2007). The shelf life of a product can be influenced by few factors such as processing method, packaging material and method and storage method and its condition (Galic et al., 2009).

Microbiological Analysis

Microbiological spoilage is usually the main issues which limit the shelf life of high and intermediate moisture bakery products, and it is also considered as the major cause of economic loss in the bakery industry (Smith, et al., 2004). Spoilage caused by microbial growth will lead to economic loss for manufacturers and consumers as well (Saranraj & Geetha, 2012). The growth of bacteria, yeasts and moulds in food products will cause food spoilage, which is associated to the human health problem due to the production of mycotoxins (Duarte et al., 2010). Fungal spoilage if of particular concern in baking products because of the high occurrence of moulds in stored agricultural products, which include wheat and corn (Eglezos et al., 2010). Fresh cookie is sterile and do not contain viable microorganisms. However, the cookie will soon become contaminated when it is exposed to the surface and air (Galic et al., 2009).

According to Saranraj & Geetha (2012), wild yeasts such as Trichosporon variable, Saccharomyces, Pichia and Zygosaccharomyces are associated to yeast spoilage in bakery products. Mould spoilage is another issue in bakery industry, which limits the shelf life of products. The most common moulds found in bakery products are Rhizopus sp., Aspergillus sp., Penicillium sp., Monilia sp., Mucor sp. and Eurotium sp. (Eglezos et al., 2010).  Generally, mould spores are killed during the baking process in fresh baked products, thus, baked products become mouldy probably due to the contamination either from air, bakery surfaces, utensils, food handlers or during the operations dealing with the raw ingredients (Saranraj & Geetha, 2012).

Water Activity Analysis

Mould spoilage which caused by the contamination of a product with fungal spores will germinate, forming a visible mycelium before consumption of the product by the consumers (Gougouli et al., 2011). Water activity is among the preservative factors which are often reported as the most effective way to inhibit the growth of mould, given that the decrease in water activity will lead to a declining speed of both the germination and growth of mycelium until a minimum where neither germination, nor growth occurs. (Dagnas et al., 2014). The water activity concept has been recognized as a reliable assessment foods in terms of the microbial growth and its chemical stability (Khouryieh & Aramouni, 2012).

Water activity is a measure of the energy level and status of water molecules, which are present in a system and its availability, acting as a solvent and involve in chemical and biochemical reactions of microbial growth. Water activityis different from the moisture content of food as water activity measures the amount of free water present in a system, on the other hand, moisture content is defined as the total amount of water which is available in food (Mckemie, 2008). It is important to measure the water activity of a food product in order to determine the shelf life the product. Water activityis the most important factor determining the type and rate of spoilage in many baked products.

The water activity is measured with a scale from 0 to 1, where 0 indicates no water and 1 indicates all water. Most of the food product are having water activity between 0.2 to 1.0. Saranraj & Geetha (2012) revealed that water activity of 0.9 support the optimum growth of bacteria while the food product with water activity above 0.6 support the growth of moulds and yeasts. There is no microbial proliferation below water activity of 0.6 (Khouryieh & Aramouni, 2012). Mundt and Wedzicha (2006) had done a research and found that the water activityin the cookie must not be higher than 0.40. Besides, based on the research done by Ameur et al. (2007), they had measured the water activity of cookie at ambient temperature, and it was quantified that the water activity of cookie must range from 0.336 ± 0.019 to 0.452 ± 0.031. Thus, there is probably no growth of microbes stated in table 2.3 in the fresh cookie where the minimum water activity level is at least 0.50. Table 2.3 shows the water activityregion for microbial growth.