Performance of Apple Pomace for Gluten-Free Bread Manufacture: Effect on Physicochemical Characteristics and Nutritional Value

Health-Promoting Properties and the Use of Fruit Pomace in the Food Industry-A Review

Fruit pomace, a by-product of the fruit industry, includes the skins, seeds, and pulp most commonly left behind after juice extraction. It is produced in large quantities: apple residues alone generate approximately 4 million tons of waste annually, which is a serious problem for the processing industry but also creates opportunities for various applications. Due to, among other properties, their high content of dietary fiber and polyphenolic compounds, fruit residues are used to design food with functional features, improving the nutritional value and health-promoting, technological, and sensory properties of food products. This article presents the health-promoting (antioxidant, antidiabetic, anti-inflammatory, and antibacterial) properties of fruit pomace. Moreover, the possibilities of their use in the food industry are characterized, with particular emphasis on bread, sweet snack products, and extruded snacks. Attention is paid to the impact of waste products from the fruit industry on the nutritional value and technological and sensory characteristics of these products. Fruit pomace is a valuable by-product whose use in the food industry can provide a sustainable solution for waste management and contribute to the development of functional food products with targeted health-promoting properties.

Quality- and Health-Promoting Compounds of Whole Wheat Bread with the Addition of Stale Bread, Cornmeal, and Apple Pomace

The aim of this study was to evaluate the effect of extruded preparations on the bioactive and nutritional properties, vitamin B content, volatile compound profile, and quality of whole wheat bread. Extruded preparations based on stale bread (secondary raw materials) and apple pomace (byproducts) were used as bread additives. It was found that the preparations did not enrich the bread in protein but in health-promoting compounds, especially gallic acid, protocatechuic acid, caffeic acid, p-coumaric acid, rutin, quercetin, and B vitamins. Extruded preparations had a positive effect on the quality of the bread produced, such as yield and cohesiveness, and gave it a pleasant aroma. It was shown that among all the examined bread samples with added extruded preparations of stale bread, the cornmeal and apple pomace bread samples with 15% extruded preparation (containing 55% cornmeal, 30% stale bread, and 15% apple pomace) had sufficient nutritional value, the highest amounts of gallic acid, protocatechuic acid, p-coumaric acid, caffeic acid, rutin, and quercetin; medium amounts of ellagic acid; high antioxidant activity determined in vitro using four methods (by DPPH, ABTS, power (FRAP), and Fe(II) chelating assays); adequate quality; and significant amounts of vitamins, especially B1, B2, and B3. This type of extruded preparation should utilize apple pomace, which is a byproduct, and stale bread, which is a secondary waste. Such a combination is an excellent low-cost, easy, and prospective solution for the baking industry that could be applied to obtain bread with elevated nutritional value and enhanced health potential, as proven in this publication.

Study on the Effect of Microwaved Brewer's Spent Grains on the Quality and Flavor Characteristics of Bread

To enable a wider utilization of co-products from beer processing and minimize the negative effect of added grain on bread quality, flavor, and other attributes, brewer's spent grains (BSG) are processed through microwave pretreatment, and then the microwave-treated BSG (MW-BSG) is added to bread. So far, there has been no investigation on the effect of microwave-pretreated BSG on bread quality and flavor. In this study, we examined the effects of diverse microwave treatment variables on the physicochemical structure of BSG and explored the consequences of MW-BSG on the quality and flavor of bread. The results showed that soluble dietary fiber and water-soluble protein levels in MW-BSG increased significantly (144.88% and 23.35%) at a 540 W microwave power, 3 min processing time, and 1:5 material-liquid ratio of BSG to water. The proper addition of MW-BSG positively affected the bread texture properties and color, but excessive amounts led to an irregular size and distribution of the bread crumbs. The result of electronic nose and HS-SPME-GC-MS analyses showed that the addition of MW-BSG modified the odor profile of the bread. A sensory evaluation showed mean scores ranging from 6.81 to 4.41 for bread containing 0-10% MW-BSG. Consumers found a maximum level of 6% MW-BSG acceptable. This study endeavors to decrease environmental contamination caused by brewing waste by broadening the methods by which beer co-products can be utilized through an innovative approach.

The effect of apple pomace powder and calcium ions on selected physicochemical properties of freeze-dried carrot-orange-ginger snacks

BACKGROUND

This study aimed to determine the effect of various amounts of dried apple pomace (AP) powder and calcium ions on selected physicochemical properties of restructured freeze-dried snacks in comparison with products obtained with low-methoxyl pectin (LMP). The material was prepared using frozen carrot, orange concentrate, ginger, water, and various concentrations of AP (1, 3, 5%) and calcium lactate (0, 0.01, 0.05%). The reference samples were without additives, and with 0.5 or 1.5% of LMP combined with 0.01% of calcium lactate.

RESULTS

The material was studied in terms of water content and activity, hygroscopic properties, structure, texture, color, and polyphenol content (TPC), and antioxidant activity. The addition of AP resulted in reducing water activity and porosity. As a consequence of the increasing density of the structure, the reduction of hygroscopic properties by up to 16% followed the increasing amount of AP. Apple pomace and calcium ions strengthened the structure. The addition of 3% and 5% of AP gave a hardening effect close to or better than 0.5% LMP. Because of the pigment dilution, LMP caused significantly greater total color change than AP. The incorporation of AP also increased TPC and enhanced antioxidant activity in comparison with the reference materials by up to 18%.

CONCLUSION

The results showed that dried AP powder can be applied successfully as an additive enhancing stability, texture and bioactive compound content, thus fortifying the physicochemical properties of restructured freeze-dried fruit and vegetable snacks. © 2023 Society of Chemical Industry.

Applications and safety aspects of bioactives obtained from by-products/wastes

Due to the negative impacts of food loss and food waste on the environment, economy, and social contexts, it is a necessity to take action in order to reduce these wastes from post-harvest to distribution. In addition to waste reduction, bioactives obtained from by-products or wastes can be utilized by new end-users by considering the safety aspects. It has been reported that physical, biological, and chemical safety features of raw materials, instruments, environment, and processing methods should be assessed before and during valorization. It has also been indicated that meat by-products/wastes including collagen, gelatin, polysaccharides, proteins, amino acids, lipids, enzymes and chitosan; dairy by-products/wastes including whey products, buttermilk and ghee residue; fruit and vegetable by-products/wastes such as pomace, leaves, skins, seeds, stems, seed oils, gums, fiber, polyphenols, starch, cellulose, galactomannan, pectin; cereal by-products/wastes like vitamins, dietary fibers, fats, proteins, starch, husk, and trub have been utilized as animal feed, food supplements, edible coating, bio-based active packaging systems, emulsifiers, water binders, gelling, stabilizing, foaming or whipping agents. This chapter will explain the safety aspects of bioactives obtained from various by-products/wastes. Additionally, applications of bioactives obtained from by-products/wastes have been included in detail by emphasizing the source, form of bioactive compound as well as the effect of said bioactive compound.

Valorization of fruit and vegetable processing by-products/wastes

Fruit and vegetable processing by-products and wastes are of great importance due to their high production volumes and their composition containing different functional compounds. Particularly, apple, grape, citrus, and tomato pomaces, potato peel, olive mill wastewater, olive pomace and olive leaves are the main by-products that are produced during processing. Besides conventional techniques, ultrasound-assisted extraction, microwave-assisted extraction, pressurized liquid extraction (sub-critical water extraction), supercritical fluid extraction, enzyme-assisted extraction, and fermentation are emerging tools for the recovery of target compounds. On the other hand, in the view of valorization, it is possible to use them in active packaging applications, as a source of bioactive compound (oil, phenolics, carotenoids), as functional ingredients and as biofertilizer and biogas sources. This chapter explains the production of fruit and vegetable processing by-products/wastes. Moreover, the valorization of functional compounds recovered from the fruit and vegetable by-products and wastes is evaluated in detail by emphasizing the type of the by-products/wastes, functional compounds obtained from these by-products/wastes, their extraction conditions and application areas.