Utilization of coconut dregs into crispy cookies as gluten-free snacks: sensory analysis and nutritional content

Coconut dregs are a by-product of processing coconut meat. Even though it is only a byproduct, coconut dregs still contain nutrients that are beneficial for the human body. It can be made as flour to make a variety of foods. The objective of this study is to identify the optimal formulation by assessing the preferences of panelists and the nutritional content of crispy cookies gluten-free products made from a mixture of composite flour of coconut dregs and red bean flour; each mixture percentage is A1 (10:90); A2 (30:70); A3 (50:50); A4 (70:30) and A5 (90:10) and coconut dregs with purple sweet potato flour at the level of each mixture percentage (%): B1 (10:90); B2 (30:70); B3 (50:50); B4 (70:30) and B5 (90:10). The test results on taste, aroma, texture, and crunchiness of crispy cookies were most preferred in treatment A5 (90:10) for a mixture of red bean flour. The nutritional value of it is 8% protein, 27% fat, 58% carbohydrates with 5.73% and coarse. In mixing with purple sweet potato flour, treatment B5 (90:10), containing 10.5% protein, 30.88% fat, and 52.83% carbohydrates with 8.63% crude fiber, was most preferred by panelists.


Introduction
Due to the variety of flavors, long shelf life, and low price, biscuits are the most popular foods among children and adults.So far, the manufacture of processed products, such as biscuits, uses wheat flour as raw material, even though Indonesia is not a wheat producer.In addition, wheat flour also contains gluten, which may cause wheat intolerance syndrome in some people and causes disturbances in the digestive system [1].Public awareness of gluten sensitivity has changed how consumers perceive and accept products, moving away from commonly found items to processed foods featuring low-gluten options.The flour processing frequently leads to decreased nutritional content and bioavailability.Composite flour made from a combination of cereals and legumes provides an alternative with lower gluten content and increased nutritional value [2].The use of gluten-free ingredients in preventing several diseases, including diabetes and chronic metabolic syndrome, has been widely practiced.Efforts include formulating ingredients low in sugar and high in fiber to reduce the glycemic index [3][4][5][6].
Efforts to reduce the consumption of wheat flour continue to be encouraged in addition to looking for alternative substitutes from other raw materials, as well as by cultivating other flours such as mixed flour (composite flour), which is a form of mixture between flour and several types of flour from other materials [7].Composite flour has carbohydrate sources (cereals and tubers).Composite flour is derived from several raw materials: tubers, nuts, or cereals with or without wheat flour.It is used as raw material 1302 (2024) 012086 IOP Publishing doi:10.1088/1755-1315/1302/1/012086 2 for processed food such as bakery and extrusion products [8].Composite flour has advantages such as higher nutritional value and more physical and organoleptic qualities than only one type of flour [9].
Generally, coconut meat is processed into copra, oil, and dregs as a by-product of coconut oil processing.It has yet to be utilized and is usually only used as animal feed [10].Based on this, coconut dregs can still be processed into flour to be used to manufacture various processed products such as bread, cakes, biscuits, and snack bars.This of course increases the function of coconut by-products for sustainability and maximizes the value of coconut for coconut farmers whose income is still relatively low, because they only rely on copra processing.
Coconut dregs flour can be an essential ingredient to make various processed foods.Coconut dregs flour is also a food source of fiber because it contains a high cellulose concentration.Fiber intake is becoming increasingly prioritized in making food product formulations because it facilitates digestion and reduces cholesterol availability in the body.Dried coconut dregs that have been fat-free contain 93% carbohydrates consisting of galactomannan 61%, mannose 26%, and cellulose 13% [11].Galactomannan can trigger the growth of intestinal bacteria that aid digestion and act as dietary fiber [12].Coconut dregs flour does not contain gluten, so using coconut dregs flour can be considered in making crispy cookies that do not require development.This snack product refers to almond crispy, which is one of the food products that is quite popular with the public because it is delicious, crunchy, and suitable for snacks in various activities.
When making cookies, local nutritious ingredients are beneficial to add to the composition of cookie ingredients, which is done by mixing the composition of dry ingredients [13].Cookies are the most popular food among children and adults due to their variety of flavors, long shelf life, and affordable price.Due to marketing competition and increasing consumer demand for natural products that are less harmful than industrial and utility products, many attempts have been made to modify the chemical composition of cookies to increase their nutritional value and functionality [14].Crispy cookies are snacks that mix dry ingredients such as flour and wet ingredients such as eggs [15].Crispy cookies are made from flour, sugar, egg whites, and vanilla extract, and the dough is baked.This product is included in the biscuits class and has crispy and dry properties [16].Making this product is easy by mixing and baking with a texture like crispy biscuits.The manufacture of crispy cookies that will be carried out in this study is generally the same as almond crispy on the market; the only difference is in the raw materials, such as wheat flour which is replaced with almond flour.The method of making and processing techniques used are all the same: baked in the oven with a thin round shape.
One of the efforts that can be made to minimize the use of wheat flour in processed food products is to replace it with food commodities in Indonesia, especially in North Sulawesi, including natural resources such as red beans, purple sweet potatoes, and even composite flour in further food processing.Red bean (Phaseolus vulgaris L.) provides vegetable protein, complex carbohydrates, fiber, B vitamins, folacin, thiamine, calcium, phosphorus, and iron.The nutritional content in 100 grams of red beans is energy of 369.35 kilocalories, protein of 22.85 grams, fat of 2.4 grams, carbohydrates of 64.15 grams, calcium 502 mg, phosphorus 429 mg, iron 10.3 mg, and fiber of 4 grams [17].Given its widespread appeal across various age groups, cookies require improved nutritional value and diversification.Red beans have the highest carbohydrate content, protein levels comparable to green beans, and fiber levels equivalent to green beans, soybeans, and peanuts.Unlike animal protein sources, red beans offer superior protein without cholesterol, making them a safe and suitable choice for consumption among diverse age groups in the community [18].
Purple sweet potato (Ipomoea batatas var Ayumurasaki) has purple-black skin and flesh.Purple sweet potatoes exhibit elevated levels of anthocyanin pigments compared to other varieties of sweet potatoes.The high anthocyanin content is the factor contributing to the purple hue of the sweet potato.Research stated that biscuits using 6% coconut dregs flour and cassava starch had the best organoleptic quality [19].
This study aims to utilize coconut dregs in composite flour as a base material for making crispy gluten-free cookies and determine the level of liking and nutritional content.The result of this study is likely to contribute to producing snack products that can be used as fiber-source snacks.

Materials and equipment
The materials used in this research were coconut dregs flour, purple sweet potato flour, egg white, granulated sugar, melted butter, vanilla extract, cornstarch, and milk powder.The equipment used in this research is PYREX™ Low-Form Glass Weighing Bottles, AND-Ex Japan Type HR analytical balance electric, Desiccator Vacuum ID 250mm Schoot DURAN, Oven Memmert UFB500, Crucible Porcelain 50ml RRC, Thermolyne Thermo Scientific 1.3L, Kjeldahl Flask IWAKI 5420 FK 500ml, Electrothermal EME60250/CEB, Electrothermal EM250 Heating Mantle, Whatman Grade 1 Qualitative Filter Paper, IWAKI Volumetric Flask, Soxhlet Extractor Apparatus IWAKI SET-250, Porcelain Buchner Funnel 800ml.

Product processing
The procedure for producing cookies adheres to the approach outlined by Rahmawati et al (2020), with modifications that include the initial phase involving the creation and roasting flour, pouring it into a separate place, mixing egg whites with powdered sugar, then mixing until stiff, then add dry ingredients such as roasted flour, powdered sugar, and vanilla powder, and stir using a plastic spatula, after all the ingredients are mixed then add liquid margarine and stir until mixed.Next, mold it with the help of a spoon.Bake until cooked at 150°C for 15 minutes.Remove, cool, and store in a tightly closed jar [21].

Research and analysis
This research method is experimental research.This research was conducted using composite flour, namely coconut dregs flour mixed with red bean flour and purple sweet potato with five formulas.The percentage proportion of coconut flour mixing is indicated in Table 1.Two grams of each sample are placed in a porcelain dish that has been pre-weighed, and the samples are then dried for three hours in an oven set at 105ºC.After cooling in a desiccator, the weight is recorded.Determining moisture content involves dividing the initial sample weight before drying and multiplying the weight loss after drying by 100%.2.3.4.Ash content.The total ash content was determined using the ash drying method.Three grams of each sample were deposited into a pre-weighed porcelain crucible and subsequently incinerated in a furnace at 550ºC until complete combustion.The crucible was then allowed to cool at room temperature inside a desiccator before being re-weighed.The total ash content is calculated as the ash weight divided by the initial sample weight multiplied by 100%.2.3.5.Protein content.Total protein content was determined through the application of the Kjeldahl method.A sample ranging from 200 to 500 mg was introduced into the Kjeldahl flask.Following this, 10 mL of solid, concentrated sulfuric acid and 5 g of catalyst (a blend of K2SO4 and CuSO4.5H2O in an 8:1 proportion) was incorporated, and the mixture underwent heating (within a fume hood) until the liquid attained a precise green coloration.After cooling, the solution was diluted with distilled water in a measuring flask to reach a volume of 100 mL.Subsequently, a 10 mL portion of the solution was transferred to the Kjeldahl distillator, and 10 mL of 30% NaOH, previously standardized with an oxalic acid solution, was introduced.Distillation occurred for approximately 20 minutes, and the resultant distillate was collected in a pre-filled 25 mL Erlenmeyer flask containing 0.1 N HCl solution standardized with borax (ensuring the condenser tip was immersed in the HCl solution).Excess HCl was titrated using 0.1 N NaOH solution, employing a mixed bromocresol green and methyl red indicator.2.3.6.Fat content.The total fat content determination is carried out through the Soxhletation method.Two grams of the sample are placed within filter paper lined with cotton, and this paper, containing the sample, is dried in an oven at a temperature not exceeding 80ºC for approximately 1 hour.Subsequently, the dried sample in the filter paper is introduced into a Soxhlet apparatus connected to a fat-bottom flask.
The sample undergoes extraction with benzene petroleum solvent for about 6 hours.The benzene petroleum is then distilled, and the resulting fat extract is dried in an oven at 105ºC, then cooled and weighed.The fat content calculation entails dividing the fat's weight by the weight of the sample and then multiplying the outcome by 100%.

Crude fiber content.
During the analysis of crude fiber, the samples undergo an extraction process involving both acid and alkali to isolate the crude fiber from other substances.An organic solvent is employed in this process, and the resulting mixture is subsequently dried and subjected to boiling after adding 50ml of a 1.25% H2SO4 solution.Following a 30-minute interval, 50ml of 3.25% NaOH is introduced, and the boiling continues for 30 minutes.The filtration is then done using a Buchner funnel equipped with pre-dried and pre-weighed Whatman filter paper.The precipitate is washed with hot 1.25% H2SO4, hot water, and 96% ethanol.Subsequent steps involve weighing and drying at 105ºC, followed by cooling and re-weighing until a constant weight is achieved.

Carbohydrate content.
The last parameter in the proximate analysis is carbohydrates, assessed through the difference method.This involves subtracting the combined moisture, ash, protein, and fat content values from 100%.

Organoleptic test
Twenty-five trained panelists conducted an organoleptic test to determine the level of panelists' preference for crispy cookies using composite flour of coconut dregs with red bean flour and purple sweet potato flour.Organoleptic test parameters include taste, color, aroma, texture, and crunchiness on a scale of 1 -7.The results of the panelists' assessment of the crisp liking test are shown in Table 2. Crispy cookies mixed with coconut dregs flour and red bean flour (A), in each treatment, produced taste values ranging from 4.96 (rather like to 5.84 (like), color ranging from 4.92 (somewhat like) to 5.08 (like), aroma ranging from 4.92-5.44(somewhat like), texture ranging from 5.04 (rather like) to 5.64 (like) and crunchiness of crispy cookies ranging from 5.48 (somewhat like) to 5.88 (like).The results of statistical analysis stated that there were no differences in the level of liking of crispy cookies in the treatment of different percentage mixtures of coconut dregs flour and red bean flour, except for the unique taste for a mixture of 90% coconut dregs flour and 10% red bean flour.The resulting data, on average, showed that the more coconut dregs flour used, the higher the panelists gave the value (more favorable).The assessment given by the panelists for the Crispy cookies mixed with coconut dregs flour and red bean flour showed that the panelists liked the taste and aroma with the texture crunchiness and brownish-yellow color.
The test results of the level of liking for the product Crispy cookies mixed with coconut dregs flour with purple sweet potato flour (B) show that, on average, there are significant differences between treatments for each parameter assessed.The level of taste preference ranged from 3.46 (somewhat dislike) to 5.6 (like), the value of color preference ranged from 3.43 (somewhat dislike) to 5.2 (somewhat like), the value of preference for aroma ranged from 3.66 (neutral) to 5.77 (like), the value of preference for texture ranged from 3.43 (somewhat dislike) to 5.60 (like) and the value of preference for crunchiness ranged from 3.16 (somewhat dislike) to 5.66 (like).Based on the data in Table 2, the more coconut dregs flour is used in the mixture with purple sweet potato flour, the more favorable the crispy cookie product is in terms of taste, aroma, texture, crunchiness, and brownish color.
The raw materials affect a difference in the shade of biscuit brightness.The reddish value indicates a reduced purple sweet potato flour concentration in the biscuits.Purple sweet potato has anthocyanin pigment, which can increase the reddish value of the biscuit.The use of purple sweet potato flour will produce a thicker colored biscuit.In expansion, the Maillard reaction can cause a brown color in biscuits that occurs when the biscuits are baked-the color of dark brown product caused by uncontrolled Maillard reaction [23].
Overall assessment for the organoleptic test, the treatment of 90% coconut dregs flour and 10% red bean flour (A5) and 90% coconut dregs flour and 10% purple sweet potato flour (B5) gave the highest average favorability scores for taste, color, aroma, texture, and crunchiness of the crispy cookies produced (Figure 1).

Nutritional content
Based on the test results of the panelists' level of liking, the nutritional content test was carried out on the protein, fat, carbohydrates, and crude fiber of crispy cookies that the panelists most liked.Nutritional content data can be seen in Table 3.The results of the nutritional content analysis showed that using coconut dregs flour as composite flour at the 90% level produced crispy cookies with good nutritional and high fiber content.The moisture content of crispy cookies as a dry biscuit product is 3.42% (A5) and 3.49% (B5).The resulting product is dry with a crunchy texture.The moisture content of this product is by SNI 2973-2018, which is a maximum of 5%.The protein content for crispy cookies treatment A5 and B5 has met the cookies standard according to SNI 2973 -2018, which is a minimum of 5%.The fat content of these crispy cookies meets the standard of cookies according to SNI 2973-2018, which is a minimum of 9.5% for both A5 and B5 treatments.
Carbohydrates significantly determine food ingredients' characteristics, such as flavor, color, and texture.Carbohydrates also prevent the onset of ketosis, assist the body's excessive protein breakdown reaction, and even greatly assist fat and protein metabolism.In addition, some carbohydrate groups produce fibers (dietary Fiber), which are helpful for digestion.The carbohydrate content of the resulting product is not by the SNI (Indonesian National Standard), which is for a minimum carbohydrate content of 70%.The crude fiber content of crispy cookies is 5.56% for mixing 10% red bean flour and 8.63% for mixing 10% purple sweet potato flour with coconut dregs flour.The amount of fiber produced in crispy cookies is quite large, so that it can be a source of fiber.

Conclusions and suggestions
The favorability test by panelists showed that cookies made from a composite flour of coconut dregs with red bean flour and purple sweet potato flour were most favored in a mixture of 90% coconut dregs flour.Crispy cookies comprise 90% coconut dregs flour and 10% red bean flour, which contains 8% protein and 27.98% fat, 58.41% carbohydrate, and 5.56% crude fiber with 517.46 kcal energy.Crispy cookies composite flour, 90% coconut dregs, and 10% purple sweet potato flour contain 10.295% protein, 30.88% fat, 52.68% carbohydrate, and 8.63% crude fiber with 555.22 kcal energy.This research shows that mixing coconut dregs is very promising for further development in the food industry because of the sensory and nutritional aspects.The innovation of this research is that it has obtained a relatively new method of processing the mixture and a formula that is acceptable to the panelists and a product from by-products with high nutrition.

Figure 1 .
Figure 1.The overall taste level of crispy cookies with coconut dregs composite flour is good.

Table 1 .
[22]formula for making crispy cookies with coconut dregs composite flour.The analysis conducted in this research was an organoleptic test conducted to determine the level of product favorability by panelists using the hedonic test.The test method carried out is the hedonic method (preference test), including the taste, color, aroma, texture, and crunchiness of the crispy cookies produced.After obtaining the results of consumer preference for the product, the most favored product is tested in the laboratory.The nutritional content test was conducted in the laboratory of the Manado Standardization and Industrial Services Center (BSPJI) based on the Indonesia National Standard (INS 01-2891-1992)[22].2.3.3.Water content.The analysis of overall water content includes performing a thermogravimetric test.
2.3.1.Organoleptic test.In this research, 25 trained panelists with expertise in sensory testing and without any health conditions (such as flu, coughs, and mouth sores) that could disrupt the organoleptic testing process were asked to provide an assessment based on their preference level.The scores used in the questionnaire are 7 (very like), 6 (like), 5 (somewhat like), 4 (neutral), 3 (somewhat dislike), 2 (dislike), and 1 (very dislike).4 2.3.2.Organoleptic parameter.

Table 2 .
Organoleptic test results of crispy cookies from coconut composite flour.
Note: Notation that present as different superscript letters on the table indicates a significant difference

Table 3 .
Nutritional content data treatment A5 and B5.