Utilization of eggshell waste in calcium-fortified foods and other industrial applications: A review

An effective preserving strategy for strawberries by constructing pectin/starch coatings reinforced with functionalized eggshell fillers

Food waste occurs frequently worldwide, though hunger and malnutrition issues have received global attention. Short-term spoilage of perishable foods causes a significant proportion of food waste. Developing simple, green, and low-cost strategies to preserve the freshness of perishable foods is important to address this issue and improving food safety. By using strawberries as the model perishable fruit, this study reported a pectin/carboxy methyl starch sodium (PC) based coating using epigallocatechin gallate-loaded eggshell powder (ES@EGCG) as the functional fillers. In comparison to PC coating, the PC-ES@EGCG coating displayed much-enhanced performance, such as enhanced mechanical (2 folds) and barrier (water vapor & oxygen) properties. This composite coating reduced the weight loss of strawberries from over 60% to around 30% after 7-day storage. Coated strawberries exhibit better freshness retention, which achieves the purpose of preserving strawberries during storage. This study provided a cost-effective and eco-friendly coating strategy for reducing food waste.

Eggshells & Eggshell Membranes- A Sustainable Resource for energy storage and energy conversion applications: A critical review

As the world strives to achieve a sustainable future, the exploration of alternative and renewable raw materials for energy storage and energy conversion has gained significant attention. A growing trend on "Waste to Energy" approach has attained prominence. Accordingly, chicken eggshells, a residual from poultry industry, have emerged as a promising candidate due to their abundant availability, low cost, and unique physical and chemical properties. This review article presents an overview of recent advancements in utilizing eggshell waste for energy storage and energy conversion applications. It discusses the transformation of eggshells usage into functional materials, along with their performance in various energy-related applications. The potential of eggshell-based materials in improving energy efficiency and reducing environmental impact is highlighted, providing insights into the future prospects of this sustainable resource.

Effect of fortification with CaCO3 nanoparticles obtained from eggshell on the physical and sensory characteristics of three food matrices

Food fortification has attracted interest in recent years, due to the understanding that micronutrient deficiency is one of the causes of the global burden of disease, and that food fortification aims to prevent or correct a demonstrated deficiency of one or more nutrients in a specific population or population groups. Nutritional value is an important concern regarding fortification and new product development. However, people are not willing to sacrifice the organoleptic characteristics of food products. Therefore, the effect of CaCO3 nanoparticles (NPs-CaCO3) and commercial CaCO3 on the physical and sensory properties of three food matrices (cookies, fruit rolls and dairy desserts) was evaluated. A texture analysis was performed on cookies and fruit rolls; a viscosity analysis on dairy desserts; and a color analysis and sensory profile on the three matrices. The results showed that both types of calcium increase hardness in fortified biscuits and fruit rolls but, in the latter case, commercial calcium caused a higher increase in hardness (p < 0.05). Viscosity was higher in the desserts with NPs. Color presented significant changes in all the fortified matrices. These findings demonstrated that Ca-NPs are a good strategy for food fortification compared to commercial calcium carbonate, as fortification with high levels of calcium is a challenge for the food industry due to its effects on the product. The results showed that, in the matrices with commercial calcium, the changes were more evident, while the matrices fortified with Ca-NP have a better sensory response than commercial Ca, with a higher level of acceptance by the judges. Therefore Ca-NPs can be considered to be a good source of calcium for food product fortification that causes a slight effect on physical and sensory properties.

Eggshell waste act as multifunctional fillers overcoming the restrictions of starch-based films

Starch has great potential to replace petroleum-based plastics in food packaging applications. However, starch films often exhibit poor mechanical and barrier properties, and are vulnerable to moisture and bacterial contamination. This study proved that the incorporation of eggshell powder (ES) enhanced the hydrogen bonding in starch-based films significantly, which contributed to improved tensile strength, Young's modulus, and water resistance of the films. The performance of ES-incorporated films could be optimized by adjusting the size, concentration, and surface property of ES in the film matrix. Notably, adsorbing epigallocatechin gallate (EGCG) on the surface of porous ES contributed to enhanced dispersibility of the fillers in the film matrix, which increased the tortuous path of light, water vapor, and oxygen have to take through the films, resulting in increased UV screening performance, water vapor and oxygen barrier property of the films by 60 %, 7.2 %, and 27.9 %, respectively. Meanwhile, loading EGCG in ES also enable superior antibacterial activity of the final films. This study suggests that eggshell fillers offer a sustainable means of improving the functional performance of starch-based films, which may increase their application as packaging materials in the food industry.

Metal-binding peptides and their potential to enhance the absorption and bioavailability of minerals

Minerals including calcium, iron, zinc, magnesium, and copper have several human nutritional functions due to their metabolic activities. Body tissues require sufficient levels of a variety of micronutrients to maintain their health. To achieve these micronutrient needs, dietary consumption must be adequate. Dietary proteins may regulate the biological functions of the body in addition to acting as nutrients. Some peptides encoded in the native protein sequences are primarily responsible for the absorption and bioavailability of minerals in physiological functions. Metal-binding peptides (MBPs) were discovered as potential agents for mineral supplements. Nevertheless, sufficient studies on how MBPs affect the biological functions of minerals are lacking. The hypothesis is that the absorption and bioavailability of minerals are significantly influenced by peptides, and these properties are further enhanced by the configuration and attribute of the metal-peptide complex. In this review, the production of MBPs is discussed using various key parameters such as the protein sources and amino acid residues, enzymatic hydrolysis, purification, sequencing and synthesis and in silico analysis of MBPs. The mechanisms of metal-peptide complexes as functional food ingredients are elucidated, including metal-peptide ratio, precursors and ligands, complexation reaction, absorbability and bioavailability. Finally, the characteristics and application of different metal-peptide complexes are also described.

High Solubility and Bioavailability of Lobster Shell-Derived Calcium for Significantly Proliferating Bone and Skin Cells In Vitro

Shell wastes pose environmental and financial burdens to the shellfish industry. Utilizing these undervalued shells for commercial chitin production could minimize their adverse impacts while maximizing economic value. Shell chitin conventionally produced through harsh chemical processes is environmentally unfriendly and infeasible for recovering compatible proteins and minerals for value-added products. However, we recently developed a microwave-intensified biorefinery that efficiently produced chitin, proteins/peptides, and minerals from lobster shells. Lobster minerals have a calcium-rich composition and biologically originated calcium is more biofunctional for use as a functional, dietary, or nutraceutical ingredient in many commercial products. This has suggested a further investigation of lobster minerals for commercial applications. In this study, the nutritional attributes, functional properties, nutraceutical effects, and cytotoxicity of lobster minerals were analyzed using in vitro simulated gastrointestinal digestion combined with growing bone (MG-63), skin (HaCaT), and macrophage (THP-1) cells. The calcium from the lobster minerals was found to be comparable to that of a commercial calcium supplement (CCS, 139 vs. 148 mg/g). In addition, beef incorporated with lobster minerals (2%, w/w) retained water better than that of casein and commercial calcium lactate (CCL, 21.1 vs. 15.1 and 13.3%), and the lobster mineral had a considerably higher oil binding capacity than its rivals (casein and CCL, 2.5 vs. 1.5 and 1.0 mL/g). Notably, the lobster mineral and its calcium were far more soluble than the CCS (98.4 vs. 18.6% for the products and 64.0 vs. 8.5% for their calcium) while the in vitro bioavailability of lobster calcium was 5.9-fold higher compared to that of the commercial product (11.95 vs. 1.99%). Furthermore, supplementing lobster minerals in media at ratios of 15%, 25%, and 35% (v/v) when growing cells did not induce any detectable changes in cell morphology and apoptosis. However, it had significant effects on cell growth and proliferation. The responses of cells after three days of culture supplemented with the lobster minerals, compared to the CCS supplementation, were significantly better with the bone cells (MG-63) and competitively quick with the skin cells (HaCaT). The cell growth reached 49.9-61.6% for the MG-63 and 42.9-53.4% for the HaCaT. Furthermore, the MG-63 and HaCaT cells proliferated considerably after seven days of incubation, reaching 100.3% for MG-63 and 115.9% for HaCaT with a lobster mineral supplementation of 15%. Macrophages (THP-1 cells) treated for 24 h with lobster minerals at concentrations of 1.24-2.89 mg/mL had no detectable changes in cell morphology while their viability was over 82.2%, far above the cytotoxicity threshold (<70%). All these results indicate that lobster minerals could be used as a source of functional or nutraceutical calcium for commercial products.

Poultry eggshell-derived antimicrobial materials: Current status and future perspectives

Poultry eggs, the basic foodstuffs of human society, have been extensively consumed for domestic and industrial uses. A large amount of eggshell waste is generated and discarded every year, resulting in a waste of natural resources and a threat to the environment. In this context, the reutilization of eggshell waste has gained increasing attentions. Meanwhile, the overuse of antibiotics has led to the emergence of many drug-resistant bacteria, which greatly endangers public health. Therefore, manufacturing new materials with strong antimicrobial activities has become the focus of many researchers. Recent studies have revealed that eggshells can be applied as solid substances, the raw materials for calcium oxide, and the calcium source for synthesizing hydroxyapatite or other materials with antimicrobial activities. Herein, the preparation methods, antibacterial mechanisms and the applications of these eggshell waste-derived antibacterial materials are summarized in this review. Finally, the current challenges and future directions in this field are discussed.

Valorization of bio-waste eggshell as a viable source of dietary calcium for confectionery products

BACKGROUND

The market of innovative foods is developing very dynamically and consumers are paying increasingly more attention to the health properties of the food offered. In addition, many studies on food consumption indicate a deficiency of minerals in the diet and experts suggest that the consumption of fortified functional foods in a selected group of consumers may contribute to the improvement of their health and quality of life.

RESULTS

The aim of the work was to present the possibility of using bio-waste eggshell as a source of calcium in designing confectionery products. A snack with high calcium (0.567 g Ca kg^-1 of product) and fiber (11.44 g kg^-1 of product) content and potentially high calcium bioavailability was prepared. The results of the sensory expert-based assessment indicate a high (6-7 conventional units) overall sensory quality (OSQ) of the four flavor versions of the product during up to 3 months storage. In order to accurately illustrate the effect of storage time on the quality of the samples, texture analysis was carried out and the presented results indicate low correlations (r = -0.5554; r = -0.1494) between instrumentally measured hardness and sensory attribute of crispness, as well as hardness and OSQ, respectively.

CONCLUSION

It is possible to reuse bio-waste eggshells as a calcium-fortifying substance for food design. The addition of powdered eggshells to food is an interesting direction, both for nutritional reasons (high concentration of calcium and optimal bioavailability) and also for environmental protection (reduction of post-production waste). © 2021 Society of Chemical Industry.

Innovative Application of 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 (p < 0.05) 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 (p < 0.05) during storage. During 2 months of storage, the antioxidative activity of gingerbread fortified with 3% ESP was not significantly different compared to the control (p > 0.05), 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 (p < 0.05). 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.

Effectiveness of Eggshells as Natural Heterogeneous Catalysts for Transesterification of Rapeseed Oil with Methanol

Heterogeneous catalysis has an advantage of easy separation of the catalyst after biodiesel is produced. CaO is known to be an efficient heterogeneous catalyst for biodiesel production. Taking into account that CaO is a key component of eggshells, the effectiveness of eggshells as a heterogeneous catalyst for rapeseed oil transesterification with methanol was investigated and optimal conditions of biodiesel production were determined applying RSM methodology. The influence of three independent variables on ester content was analyzed and a quadratic model was created. It was determined that this model is statistically significant. The optimum transesterification conditions when eggshells are used as a heterogeneous catalyst, and the process temperature of 64 °C, were determined as: the methanol-to-oil molar ratio 10.93:1; the catalyst amount 6.80 wt%; the reaction duration 9.48 h. The ester yield of 97.79 wt% was obtained under these conditions.