Chicken Eggshell Calcium to Improve the Functional Value of Gingerbread -

Chicken Eggshell Calcium to Improve the Functional Value of Gingerbread

Food waste, such as eggshell, can be an environmental problem if it is not properly managed. One of the ways to solve this is by using the eggshell as the cheap calcium source in food products. Polish gingerbread fortified with chicken eggshell powder (ESP) calcium was developed to solve the eggshell waste problem and to reduce the risk of osteoporosis. This study focused on the effect of ESP addition on basic composition, sensory evaluation, and antioxidative activity of gingerbread. Two samples of gingerbread without and with 3% (w/w of wheat flour) ESP, with controlled green tea powder (4% w/w of white chocolate) were analyzed. Results of the research showed that the addition of 3% ESP significantly increased the ash and calcium content without changing the appearance, aroma, texture, taste profiles, and the hedonic score of gingerbread. The gingerbread samples were then stored for 2 months and were analyzed every month. The hedonic evaluation of the aroma of both gingerbread samples decreased significantly during storage. During 2 months of storage, the antioxidative activity of gingerbread fortified with 3% ESP was not significantly different compared to the control, particularly in ABTS and ORACFL assay. The ABTS, DPPH, and ORACFL assays showed decreasing antioxidative activity during storage, which was also in accordance with decreasing total phenolic content of both gingerbread samples. In PCL assay, the lipid-soluble antioxidant activity in gingerbread with 3% ESP was significantly higher during 2 months of storage, compared to the control. The developed product might be a potential alternative to improve the calcium (26% daily value (DV) recommendation per 100 g and antioxidant intake in order to prevent calcium deficiency. Gingerbread enriched with an organic source of calcium may become an innovative product to reduce the risk of developing osteoporosis in the elderly population, having potential health and economic significance, given the incidence of osteoporosis and the costs of treating this disease.

Material and Methods

Preparation of Eggshell Powder and Gingerbread

The collected chicken eggshells were washed and scrubbed using a sponge and running water. The clean eggshells were then boiled in water for 30 min. The drying and sterilizing process was conducted using a hot air oven at 134 ◦C for 15 min. A was used to grind the sterilized eggshells. The eggshell powder (size ≤ 0.315 mm) was collected after the sieving process. The ingredients used in the preparation of gingerbread samples were: UHT milk 3.2% fat, unrefined cane sugar, dry yeast, white flour type 650, oat bran, salt, honey, egg, baking soda, gingerbread spice mix (containing sugar, cinnamon 15%, cloves, fat-reduced cocoa, coriander fruit, allspice, nutmeg), butter 82% fat, white chocolate, green tea powder and eggshell powder. The concentration of eggshell powder (3% w/w of flour) and green tea powder was determined after considering prior research. However, from the preliminary evaluation of the present study the addition of eggshell powder more than 3% w/w of flour resulted in a more noticeable undesired typical eggshell aroma. The used concentration of green tea powder was 4% (w/w) of white chocolate topping in both control and treatment samples. The addition of green tea powder higher than 4% resulted in unacceptable taste due to high astringency and grassy aftertaste.

Basic Composition Analysis

The basic composition of gingerbread samples included lipid, protein, ash, moisture, carbohydrate, fiber, and calcium content. Soxhlet method using Soxtec-HT6 System was conducted in lipid extraction. The Kjeldahl method with the use of Kjeltec-2200 System following AOAC was conducted to determine the protein content. The ash content was determined after complete incineration of the sample at 530 °C for 8 h, using a muffle furnace, according to AOAC. For moisture content determination, the samples were dried in the oven at 105 °C. The weight of the sample was recorded several times and placed back in the oven until the weight was stable. The carbohydrate content was obtained after calculation of 100%, subtracted by the total sum of lipid, protein, moisture, and ash content. The energy value was calculated using the following conversion factors: carbohydrate 4 kcal/g, protein 4 kcal/g, and lipid 9 kcal/g. The determination of fiber content was measured as total dietary fiber (TDF), insoluble dietary fiber (IDF), and soluble dietary fiber (SDF) following the enzymatic-gravimetric Asp method. Other fiber fractions, including neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin (ADL), and cellulose (ADC), were determined following Van Soest assay. Prior to the determination of calcium content, the complete mineralization of 1 g of samples (powdered form) at 450 °C in a muffle furnace was conducted. It was then dissolved in 1 mol/L nitric acid. Analysis of the sample was conducted in triplicate. The samples were diluted with 0.5% LaCl₃. Atomic absorption spectrometry using an air-acetylene flame was conducted to determine the calcium content of gingerbread samples.

Total Phenolic Content and Antioxidative Activity Analysis

For the evaluation of total phenolic content and antioxidative activity of gingerbread samples during storage, the samples were stored in a thermostat (20 °C) in a dark condition for 2 months. This period of storage was decided based on the approximate time that the consumer could store the product on a shelf without quality loss. Total phenolic content (TPC) was determined based on the reduction of Folin–Ciocalteu reagent complexes, measured at λ = 725 nm, expressed as mg of gallic acid equivalent (GAE) per 100 g of product. Prior to antioxidant activity analysis, the samples (3.5 ± 0.1 g) were lyophilized, ground, and extracted using 80% methanol (100 mL) for 2 h at 20 °C.

Sensory Analysis

The sensory analysis of fresh gingerbread samples, with and without eggshell powder, with controlled green tea concentration was conducted by 15 trained panelists after the production of the samples (not more than 24 h). The sensory analysis was divided into two sections: sensory profiling and hedonic test. In sensory profiling, the panelists evaluated the appearance, aroma, texture, and taste of the fresh samples, with a range of 0 (absent) to 9 (very high/very intensive). The descriptions included: appearance (surface color uniformity, glossiness, smoothness, brightness), aroma (spiciness, chocolate, green tea, sweetness, burnt, rancidity), texture (softness, humidity, porosity, crispness, adhesiveness, grittiness), and taste (sweetness, saltiness, spiciness, burnt, rancidity, strong). While in hedonic evaluation, the panelists evaluated the appearance, aroma, texture, taste, and overall, with the scale ranging from 1 (dislike extremely) to 9 (like extremely). Additionally, for storage analysis, the hedonic evaluation of the gingerbread samples was also conducted by 14 consumer panelists. During 2 months of storage, the gingerbread samples were kept in the dark condition under a controlled temperature (20 ◦C). The condition and period of storage were selected according to the approximate time that the consumer could store the product on the shelf without quality loss. The sensory analysis was conducted in the sensory analysis room, and all the consumer panelists were trained for the testing procedure.

Conclusions

In this study, the innovative functional food based on gingerbread enriched with antioxidants from green tea and chicken eggshell calcium was developed. The addition of 3% (w/w of wheat flour) eggshell powder improved the ash and calcium content of the gingerbread without significantly changing the appearance, aroma, texture, taste, and the hedonic score of gingerbread in comparison with gingerbread without eggshell powder. About 26% DV of calcium could be fulfilled by consuming 100 g of gingerbread fortified with 3% ESP (assuming that the calcium is 46% bioavailable). The addition of eggshell powder significantly increased the content of hemicellulose, soluble, insoluble, and total dietary fiber of gingerbread. It was also observed that the soluble dietary fiber was predominant in gingerbread fortified with 3% ESP, which might potentially have a role as a prebiotic agent and then might increase the bioavailability of microminerals, including calcium. The fortification of 3% ESP to the gingerbread did not change the antioxidative activity in ABTS and ORACFL assay. The antioxidative activities and hedonic scores of both gingerbread samples decreased during 2 months of storage. However, both samples still possessed antioxidative activity and moderate consumer acceptability after 2 months of storage. In industrial production, the sterilization and grinding process of eggshells must be conducted properly to obtain safe and sensorially acceptable eggshell powder. Although the gingerbread in this study contained increased calcium content and antioxidative activity, the sugar consumption should be reduced in further studies following the current health trend in reducing high sugar intake. The information observed in this research could be useful for scientific knowledge, especially as one of the alternative ways to solve eggshell waste problem by incorporating it into gingerbread to decrease calcium deficiency and the risk of osteoporosis, which are global health problems.

Citation:

Arnold, M., Rajagukguk, Y.V., Sidor, A., Kulczyński, B., Brzozowska, A., Suliburska, J., Wawrzyniak, N. and Gramza-Michałowska, A., 2022. Innovative Application of Chicken Eggshell Calcium to Improve the Functional Value of Gingerbread. International Journal of Environmental Research and Public Health, 19(7), p.4195.