Processing of Apple Pomace for Bioactive Molecules

A New Approach to Recover Bioactive Compounds from Apple Pomace: Healthy Jelly Candies

Rich in bioactive compounds, carbohydrates, fibers, minerals, and trace elements, apple pomace (AP) is a significant agro-industrial by-product, which pollutes and brings high management costs. The current study investigates the possibility of using an aqueous AP extract (APE) as the main ingredient in a jelly candy recipe, replacing artificial colors and flavors and improving its nutritional value. APE and formulated jelly candies were analyzed in terms of their phytochemical profile, antioxidant capacity, and color parameters. In addition, the microbiological and sensory properties of the jelly candies, as well as their behavior during storage, were analyzed. An HPLC analysis of AP revealed the presence of 9 individual phenolic compounds, with a high content of protocatechuic (375.21 ± 18.76 µg/g DW) and p-hydroxybenzoic (164.96 ± 13.83 µg/g DW) acids. The results of this study prove the presence of bioactive compounds with antioxidant and antidiabetic properties in both APE and its candies. Investigation on jelly candies with APE revealed an antioxidant capacity of 142.03 ± 1.08 mmol TE/g DW and a total polyphenolic content of 8.25 ± 0.17 mg GAE/g DW. Additionally, a sensory analysis highly appreciated the proposed jelly with APE, with scores higher than 4.70/5.00 for all evaluated attributes. Thus, this study succeeded in developing a new approach to recovering bioactive compounds from AP, demonstrating the potential of this by-product to improve jelly candies' attributes while promoting sustainability through waste reduction and the effective use of natural resources.

Effects of substituting soybean meal with fermented rapeseed meal mixture on the growth performance, slaughter performance, meat quality, blood biochemical indices and intestinal barrier function in Langshan Chickens

This study aimed to explore the effects of substituting soybean meal with a mixture of solid-state fermented rapeseed meal, apple pomace, and wheat bran on the growth performance, slaughter performance, meat quality, blood biochemical indices and intestinal barrier function of Langshan chickens. A total of 144 30-day-old Langshan chickens with similar body weights were randomly divided into three treatment groups, with six replicates per group and eight chickens per replicate: the control group (CON) was fed a corn-soybean meal basal diet, while the rapeseed meal mixture group (RSM) and the fermented rapeseed meal mixture group (FRSM) were fed diets substituting 5 % of soybean meal with rapeseed meal mixture and fermented rapeseed meal mixture, respectively. The trial lasted from 30 to 58 days of age. The results showed that compared to the CON group, the RSM group exhibited no significant changes in average daily feed intake (ADFI), average daily gain (ADG) and feed to gain ratio (F/G) (P > 0.05); the dressing percentage, half-eviscerated yield and eviscerated yield decreased (P < 0.05); the pH24h and yellowness of breast muscle increased (P < 0.05); the crypt depth of the jejunum decreased, and the villus height/crypt depth ratio increased (P < 0.05); the serum D-lactic acid content decreased (P < 0.05). Compared to the CON group, the FRSM group exhibited no significant changes in ADFI, ADG and F/G (P > 0.05); the eviscerated yield increased (P < 0.05); the serum glucose and uric acid levels decreased (P < 0.05); the crypt depth of the jejunum decreased, and the villus height/crypt depth ratio increased (P < 0.05); the serum D-lactic acid content decreased (P < 0.05). Furthermore, compared to the RSM group, the FRSM group exhibited no significant changes in ADFI, ADG and F/G (P > 0.05); the dressing percentage, half-eviscerated yield and eviscerated yield increased (P < 0.05); the pH24h of breast muscle decreased; the serum glucose and uric acid levels decreased (P < 0.05).In conclusion, RSM reduced the slaughter performance of Langshan chickens, while FRSM improved their slaughter performance. Both RSM and FRSM improved the jejunal morphology and intestinal permeability in Langshan chickens. In conclusion, fermentation improved the feed value of the rapeseed meal mixture; replacing part of the soybean meal diet with fermented rapeseed meal mixture helped improve the slaughter performance and intestinal barrier of Langshan chickens.

Application of statistical designs strategy to improve cellulase production using agro-waste residue by a novel isolate Bacillus licheniformis strain-MA1 and assessing the enzyme effect on apple juice quality

BACKGROUND

Cellulose is the major part of lignocellulosic biomass. It can be hydrolyzed into glucose units via specific enzymes called cellulases that have been applied in many commercial fields. There are several studies illustrate the influence of enzymes on apple juice clarification. However, to the best of our knowledge, the effect of microbial cellulase on volatile compounds of apple juice is not well known. The present study aimed to assess the effect of cellulase from a new bacterial isolate on the physicochemical properties of apple juice as well as volatile compounds. The hydrolysis of some polysaccharides (cellulose, hemicellulose, pectin) and polyphenols during apple juice production is necessary to reduce cloud sedimentation or color deterioration and increase the yield of juice. So, enzymes from new microbial isolates serve as processing aids to obtain clear juice with a high yield.

RESULTS

Cellulase-producing bacterium was isolated, characterized and molecularly identified as Bacillus licheniformis strain-MA1 with an accession number of ON840115. Optimization of medium parameters was implemented using Plackett-Burman design (PBd) followed by Box-Behnken design (BBd) of response surface methodology (RSM). The PBd revealed the three most important (significant) variables including carboxymethyl cellulose (CMC), corn cob, and peptone that had positive impact on cellulase production. Additionally, using the agricultural residue (corn cob) by the bacterial strain as a carbon source helps in reducing the costs of enzyme production, recycling the by-products, and preserving the environment. The optimized medium using PBd and BBd enhanced cellulase production from B. licheniformis strain-MA1 by 6.8-fold. A remarkable increase was observed in juice yield in enzyme treated-juice sample (88.2 ± 0.15%) in comparison with control juice (75.4 ± 0.09%). The total phenolic contents in cloudy and clarified apple juices were 0.957 ± 0.09 and 0.412 ± 0.03 mg/mL, respectively. Also, DPPH and FRAP assays showed a remarkable increase in antioxidant activity (Low IC50) in the control sample compared to enzyme treatment. Twenty-seven volatile compounds were extracted using headspace solid-phase microextraction-gas and analysis was performed by GC-MS. The identified volatile constituents belonged to several chemical classes: 15 esters; 6 alcohols; 4 aldehydes and 2 acids. The predominant class in apple juice volatile fraction was esters with a sweet and fruity odor.

CONCLUSION

The crude cellulase obtained from the novel bacterial isolate B. licheniformis strain-MA1 was successfully applied as a clarifying agent in apple juice.

Dynamics of cyanogenic glycosides in apple and plum fruits, products, and byproducts: A concise review

Apples (Malus domestica) and plums (Prunus domestica) are important fruit crops belonging to the Rosaceae family. The edible parts of fruits and seeds contain phytochemicals; however, the seeds are rich in cyanogenic glycosides (CNGs), which release toxic hydrogen cyanide (HCN) upon the loss of plant cell integrity. This review aims to explore the quantitative and qualitative CNG profiles in apples and plums, focusing on their distribution in different parts of the fruit, changes during fruit development, and environmental impacts on their biosynthesis. It also discusses the intricate dynamics of CNGs in processed fruits and waste-derived products and the effects of the processing methods on CNG content. There is considerable variation in the CNG content of fruit crops, as well as in its distribution in fruit parts other than seeds and shifts during fruit maturation. Although several studies have attempted to explain this variability by the influence of cultivars and exogenous factors, there is insufficient evidence to draw reliable conclusions. Furthermore, due to the lack of studies, the dynamics of CNGs during the storage of fresh or preserved fruit remains unaddressed. In the context of reusing plum stones from waste to produce distillates, it is recommended to monitor the HCN content in the products during storage, as it can increase significantly over time. Processing methods influence CNG levels, with strategies like seed separation, soaking, and microwave heating showing promise in reducing cyanide (CN-) presence. The insights from this review will provide direction for future detailed research.

An Overview of Apple Varieties and the Importance of Apple Consumption in the Prevention of Non-Communicable Diseases-A Narrative Review

Non-communicable diseases such as cardiovascular diseases, cancers, diabetes, and asthma are increasingly common due to factors like industrialization, urbanization, fast-paced life, stress, sedentary lifestyle, and unbalanced diet in the 21st century. These chronic conditions are a global epidemic, being among the top causes of death worldwide. Preventing these diseases through a nutritious diet is crucial, and scientific studies suggest that appropriate fruit intake, particularly apples, can lower the risk of various health issues. Apples, rich in bioactive compounds, vitamins, minerals, and dietary fiber, offer numerous health benefits. Regular consumption of apples helps reduce the risk of atherosclerosis, coronary artery disease, heart attacks, and diabetes, and also provides anti-asthmatic and anti-allergic effects. Apples aid in detoxification, improve digestion, enhance skin, hair, and nail health, and offer protection against cancers, Alzheimer's, and Parkinson's disease. Apples have been a dietary staple for centuries, consumed in various forms like juices, sauces, and ciders. The reviewed article emphasizes the health benefits of apples, highlighting their role in preventing civilization diseases. It also discusses the characteristics of common apple varieties and the impact of thermal processing on their nutritional content.

Sustainable Jam with Apple Pomace: Gelling, Rheology, and Composition Analysis

Fruit juice processing can generate significant waste, but efficiently repurposing some of its byproducts not only reduces environmental impact but also adds value, thereby enhancing sustainability in the food industry. This work assesses the use of hydrocolloids in jam preparation and the influence of time and temperature on gelation in the presence of apple pomace. The effects of different processing conditions were analyzed using response surface methodology. Viscosity, elastic modulus (G'), viscous modulus (G″), and firmness were measured. Results indicated that both time and temperature significantly improved rheological and textural properties. The optimal conditions (35.6 min and 84.2 °C) yielded a viscosity of 3.66 × 10⁴ ± 4.49 × 102 Pa·s and a G' at 1 Hz of 2596 ± 128 Pa. The final product exhibited the desirable texture, was free of added sugars, had low lipid content, and retained its bioactive compounds. Applying apple pomace in the formulation allows a more efficient hydrocolloid system, promotes a circular economy, and combats food waste.

Utilization and Effect of Apple Pomace Powder on Quality Characteristics of Turkey Sausages

The present study was conducted to develop turkey sausages by incorporating freeze-dried apple pomace (FDAP) at 3, 5, and 8% by replacing turkey breast meat. Three sausage formulations and the control of turkey sausages were subjected to physicochemical properties: proximate content, water-holding capacity (WHC), cooking yield, pH, color, textural parameters, antioxidant activity, and microbiological and sensory properties. The parameters were analyzed during storage from days 0 to 7. The addition of FDAP to turkey sausages resulted in a significant (p ≤ 0.05) decrease in moisture and protein contents, whereas no significant difference was found in fat and ash contents. The increased incorporation of FDAP resulted in decreased pH, cooking loss, lightness, redness, and yellowness in turkey sausages, whereas an increase in total phenolic content, fiber content, ABTS, and DPPH values was observed. FDAP, as a low-cost source of valuable phenolic content, strongly inhibited microorganism growth during the storage of turkey sausages. The sensory scores of turkey sausages containing 3% FDAP for other sensory traits, such as flavor, texture, juiciness, tenderness, and overall acceptability, were comparable to those of the control. Scores for sensory attributes declined significantly with a further increase in FDAP in turkey sausages. It is concluded that turkey sausages with very good acceptability can be prepared by incorporating freeze-dried apple pomace each at a 3% level.

A novel g-C3N4-SH@konjac glucomannan composite aerogel for patulin removal from apple juice and its photocatalytic regeneration

Patulin (PAT) is a hazardous mycotoxin frequently occurs in fruit industry. A reusable g-C3N4-SH@KG composite aerogel for PAT removal in a novel "dark adsorption-light regeneration" mode was prepared by thiol(-SH) functionalization and konjac glucomannan (KG) immobilization. The g-C3N4-SH@KG was characterized by SEM, FT-IR, XPS and UV-Vis DRS, and its PAT adsorption and photocatalytic regeneration behaviors and mechanisms were investigated. The g-C3N4-SH@KG exhibited good regeneration performance, maintaining 83% of PAT initial adsorption capacity (0.92 mg/g) after 5 "adsorption-regeneration" cycles. The adsorption process was endothermic and spontaneous. •OH and h+ generated by photocatalysis were the main substances that degraded PAT into two products and regenerated -SH. The g-C3N4-SH@KG could effectively remove PAT without negative impact on juice quality. The study provided a new strategy for the regeneration of thiol-functionalized PAT adsorbents, and a new idea for the application of non-selective photocatalysis in the control of food contaminations.

New Strategy for Browning Prevention in Apple Pomace Processing and Toxicity Tested in a Rodent Model

Apple pomace (AP) is a byproduct of apple juice industries, which constitutes around 30% of the original fruit and rich in essential compounds like carbohydrates, phenolics, minerals, and dietary fibers. This study is focused on optimizing the combinational utilization of antibrowning agents like l-cysteine and l-ascorbic acid for the sustainable debrowning of AP with response surface methodology and assessment of its acute toxicity in female rats. In addition, the phytochemical content and antioxidant activity of treated AP were investigated and compared with the untreated control AP. The study revealed that the treated AP has higher dietary fiber (p < 0.01), protein (p < 0.0001), and phenolic content (p < 0.001) in comparison to the control AP. Moreover, the treated AP also observed with higher antioxidant activity 37% inhibition and water retention capacity (8.5 g H2O/g solid) along with the debrowning effect. Furthermore, a 4-week in vivo study is conducted to assess the toxicity of treated AP. Results indicated no discernible variations in biochemistry, morphometric, or histology between the supplementation (0.5, 1.5, and 3% AP) and control groups. Thus, adding AP rich in dietary fiber to a range of meals is deemed a safe and valuable food supplement.

Effects of apples (Malus domestica) and their derivatives on metabolic conditions related to inflammation and oxidative stress and an overview of by-products use in food processing

Apple (Malus domestica) is the third most produced fruit worldwide. It is a well-known source of bioactive compounds mainly represented by hydroxycinnamic acids, flavan-3-ols, dihydrochalcones, dehydroascorbic acid, carotenoids, chlorogenic acid, epicatechin, and phloridzin. Due to the lack of a recent evaluation of the clinical trials associated with apple consumption, this review investigated the effects of this fruit on metabolic conditions related to inflammation and oxidative stress and reviewed the applications of apple waste on food products. Thirty-three studies showed that apples or its derivatives exhibit anti-inflammatory and antioxidant actions, improve blood pressure, body fat, insulin resistance, dyslipidemia, and reduce cardiovascular risks. Apples have a great economic impact due to its several applications in the food industry and as a food supplement since it has impressive nutritional value. Dietary fiber from the fruit pomace can be used as a substitute for fat in food products or as an improver of fiber content in meat products. It can also be used in bakery and confectionary products or be fermented to produce alcohol. Pomace phytocompounds can also be isolated and applied as antioxidants in food products. The potential for the use of apples and by-products in the food industry can reduce environmental damage.

Selected fruit pomaces: Nutritional profile, health benefits, and applications in functional foods and feeds

The utmost objective of every nation is to achieve zero hunger and ensure the health and well-being of its population. However, in impoverished nations, particularly in rural areas, such issues persist on a daily basis. Currently, there is a growing demand for fruit consumption due to their potential health benefits. Surprisingly, their most prevalent by-product is pomace, which is produced in millions of tonnes and is usually discarded as waste after processing or consumption. Even food produced with these kinds of raw resources can contribute to the objective of eradicating world hunger. Owing to these advantages, scientists have begun evaluating the nutritional content of various fruit pomace varieties as well as the chemical composition in different bioactive constituents, which have significant health benefits and can be used to formulate a variety of food products with notable nutraceutical and functional potential. So, the purpose of this review is to understand the existing familiarity of nutritional and phytochemical composition of selected fruit pomaces, those derived from pineapple, orange, grape, apple, and tomato. Furthermore, this article covers pre-clinical and clinical investigations conducted on the selected fruit pomace extracts and/or powder forms and its incorporation into food products and animal feed. Adding fruit pomaces reduces the glycemic index, increases the fibre content and total polyphenolic contents, and reduces the cooking loss, etc. In animal feeds, incorporating fruit pomaces improves the antioxidant enzyme activities, humoral immune system, and growth performance and reduces methane emission.

Sustainable utilization of apple pomace and its emerging potential for development of functional foods

Apple pomace, a byproduct of apple processing industry, possesses nutritional components which are of great interests for health aspects. Apple pomace is a good source of dietary fiber, minerals, carbohydrates, phenolic, and antioxidant compounds. These bioactive compounds can be extracted by different extraction techniques which have been comprehensively described in this review article. Furthermore, the incorporation of apple pomace as functional ingredients in different food products like bakery items, extrusion-based snacks, meat, dairy, and confectionary products to improve the commercial value and health benefits has been discussed briefly. This review article can be a helpful tool for industrialists, innovative researchers, and waste management authorities to manage the apple waste in an appropriate and sustainable way.

Effects of Particle Size on Physicochemical and Nutritional Properties and Antioxidant Activity of Apple and Carrot Pomaces

The food processing industry is growing rapidly and producing large amounts of by-products, such as pomaces, which are considered as no-value waste and cause significant environmental pollution. The main by-products of fruit juice processing companies are apple and carrot pomaces, which can be used to create new functional food products. In the present study, the effects of particle size (PS) on the proximate composition, nutritional properties, and antioxidant activity of apple pomace flour (APF) and carrot pomace flour (CPF) were determined. Four different PS fractions, PS > 1 mm, 1 > PS > 0.71 mm, 0.71 > PS > 0.18 mm, and 0.18 > PS > 0.075 mm were used for the present study. Their vitamin, carotenoid, organic acid, and reducing sugar contents were determined using HPLC. The proximate compositions of each PS fraction of the AP and CP flours were determined using recommended international standard methods. DPPH, FRAP, and Folin-Ciocalteu methods were used to measure their antioxidant activity and total phenolic compounds, respectively. The moisture content (around 12.1 mg/100 g) was similar in all PS fractions and in both flours. The APF had lower protein (4.3-4.6 g/100 g dw) and ash (1.7-2.0 g/100 g dw) contents compared to the CPF, with protein contents ranging from 6.4-6.8 g/100 g dw and ash contents ranging from 5.8-6.1 g/100 g dw. Smaller particles, regardless of flour type, exhibited higher sugar and phenolic contents and antioxidant activity, while vitamins were more abundant in particles larger than 1 mm. In the APF, larger particles had a higher fiber content than smaller particles, while their fat content was the lowest. PS also had an impact on the results of the carotenoid contents. This study underscores the direct impact of PS on the distribution of sugars, crude fiber, fat, carotenoids, vitamins, total phenolic compounds, and antioxidant activity in pomaces.

Exploring apple pectic polysaccharides: Extraction, characterization, and biological activities - A comprehensive review

Apple (Malus domestica) is a popular and ancient fruit of the Myrtaceae family. Apple fruit is well-known for its great nutritional and phytochemical content consisted of beneficial compounds such as polyphenols, polysaccharides, sterols, and organic acids. Polysaccharides extracted from different parts of the apple fruit, including the peel, pomace, or the whole fruit, have been extensively studied. Researchers have investigated the structural characteristics of these polysaccharides, such as molecular weight, type of monosaccharide unit, type of linkage and its position and arrangement. Besides this, functional properties and physicochemical and of apple polysaccharides have also been studied, along with the effects of extraction procedures, storage, and processing on cell wall polysaccharides. Various extraction techniques, including hot water extraction, enzymatic extraction, and solvent-assisted extraction, have been studied. From the findings, it was evident that apple polysaccharides are mainly composed of (1 → 3), (1 → 6): α-β-glycosidic linkage. Moreover, the apple polysaccharides were demonstrated to exhibit antioxidant, hepatoprotective, anti-cancer, hypoilipidemic, and enzyme inhibitory properties in vitro and in vivo. The potential applications of apple polysaccharides in the food, cosmetic, pharmaceutical, nutraceutical industries have also been explored in the present review. Overall, the research on apple polysaccharides highlights their significant potential as a source of biologically active compounds with various health benefits and practical applications.

Traditional uses, chemical composition, and pharmacological effects of diaphragma juglandis fructus: A review

ETHNOPHARMACOLOGICAL RELEVANCE

In traditional Uyghur medicine, diaphragma juglandis fructus (DJF) has been conventionally used in treating insomnia and nourishing the kidneys. According to traditional Chinese medicine, DJF can boosts kidney and astringent essence, strengthen the spleen and kidney, exert diuretic effect, clear heat, stop eructation, and treat vomiting.

AIM OF THE REVIEW

Research on DJF has increased gradually in recent years, but reviews of its traditional uses, chemical composition, and pharmacological activities are scarce. The purpose of this review is to analyze the traditional uses, chemical composition, and pharmacological activities of DJF and provide an overview of the findings for further research and development of DJF resources.

MATERIALS AND METHODS

Data on DJF were obtained from different databases, including Scifinder, PubMed, Web of Science, Science Direct, Springer, Wiley, ACS, CNKI, Baidu Scholar, and Google Scholar; books; and Ph.D. and MSc theses.

RESULTS

According to traditional Chinese medicine, DJF has astringent properties, inhibits bleeding and banding, strengthens the spleen and kidneys, acts as a sleeping aid by reducing anxiety, and relieves dysentery due to heat exposure. The components of DJF include flavonoids, phenolic acids, quinones, steroids, lignans, and volatile oils, which exhibit good antioxidant, antitumor, antidiabetic, antibacterial, anti-inflammatory, and sedative-hypnotic properties, and present therapeutic potential for kidney diseases.

CONCLUSIONS

Based on its traditional use, chemical composition, and pharmacological activities, DJF is a promising source of natural medicine in the development of functional foods, drugs, and cosmetics.

Apple Pomace Compositional Data Highlighting the Proportional Contribution of Polymeric Procyanidins

Recent years have seen an increase in research focusing on the amelioration of apple pomace waste for use in the food and nutraceutical industries. Much of this work has concentrated on the characterisation of the polyphenol composition of apple pomace materials to determine their role in conferring nutritional and health benefits. Although apples contain substantial quantities of polymeric procyanidins (condensed tannins), this class of compounds has received limited attention in apple research. This study quantified the polymeric procyanidins in apple pomace extracts using a rapid, methyl-cellulose precipitation (MCP) approach for the first time. In addition, a non-targeted metabolomics approach was applied to determine the most abundant phenolic classes present. Polymeric procyanidins were found to be the most abundant type of polyphenol in apple pomace extracts and were generally oligomeric in nature. Multivariate statistical analysis revealed that the ferric-reducing antioxidant power (FRAP) was most strongly correlated with the polymeric procyanidin concentration. Noting that polymeric procyanidins may not cross the cell layer to exert antioxidant activity in vivo, their presence in apple pomace extracts may therefore overestimate the FRAP. This work highlights the importance of polymeric procyanidins in the phenolic diversity of apple pomaces, and it is proposed that in future studies, rapid MCP assays may be used for their quantification.

Advances in apple packaging: a review

Apple (Malus domestica) belongs to the family Rosaceae. It is one of the most commonly cultivated fruit in all temperate zones of the world and holds an equally important place in the global economy. Apple is a climacteric fruit and undergoes metabolic changes even after the harvest and thus prone to post-harvest losses. The packaging of apples plays an important role in extending the shelf life of the apples and also maintains the quality during distribution and transport. The prime role of packaging is to contain the food commodity and protect the enclosed product from external damage. But other functions such as traceability, convenience and temper evidence are of secondary importance. Different packaging techniques are employed for the packaging of apples which include both conventional (wooden boxes, corrugated fiber boxes, crates) and non-conventional packaging like modified atmosphere packaging (MAP), active packaging, edible coatings, etc.

Multivariate analysis of structural and functional properties of fibres from apple pomace using different extraction methods

In recent years, diets rich in fibres have become more popular due to their well-documented beneficial health effects. This has driven exploration of novel dietary fibres from various bioresources. Apple pomace, an industrial waste rich in fibres was used in this study to extract the insoluble dietary fibres. The effect of various extraction methods (hot water, acid, and alkali) on the physico-chemical, structural and functional properties, and prebiotic activity of dietary fibres was evaluated. Hot water extraction resulted in highest yield of dietary fibres in comparison to other methods (p < 0.05). All the fractions resulted in different organization of fibrous components as depicted by scanning electron micrographs, Fourier Transform Infrared spectroscopy (FTIR), X-Ray Diffraction (XRD) pattern and Thermo Gravimetric Analysis (TGA). The acid extracted fibre fraction was observed to be amorphous with loose and porous structure whereas the alkali extracted fraction was more thermal stable based on TGA profile. Among the functional properties, acid extracted dietary fibres fraction possessed highest water and oil holding capacity (p < 0.05). The hot water extracted dietary fraction resulted in maximum increase in viable cell count of standard probiotic strains Lactobacillus sporogenes and Streptococcus faecalis. The Principal Component Analysis revealed that acid extracted fraction possessed better functional activity which also correlates with the structural properties whereas for prebiotic activities, the fibre obtained from hot water extraction method served the best method. These results indicate that dietary fibres extracted through hot water can be employed as a potential prebiotic substrate for the probiotic cultures and could be further explored in foods to improve textural, functional, and bioactive properties of foods.

Graphical Abstract

Phenolic Compounds and Antioxidant Status of Cookies Supplemented with Apple Pomace

The post-production leftovers after the pressing of apple juice are a rich source of health-promoting compounds, which could be used in the food industry for the manufacture of dietary foods, applicable also for people with celiac disease. This raw material is currently little used, and the cost of its disposal is considerable. Therefore, an attempt was made to enrich gluten-free cookies with different proportions of apple pomace. The content of individual polyphenols determined by the UPLC-PDA-MS/MS method, basic chemical composition, physical properties of cookies with 15%, 30%, 45%, and 60% apple pomace, were evaluated. It was found that apple pomace in gluten-free cookies caused an increase in the content of phenolic acids, quercetin derivatives, flavan-3-ols and dihydrochalcones. An elevation in protein, fat, and minerals was also observed. The growing share of apple pomace caused a significant increase in the content of total fiber, soluble, and insoluble fractions, but resulted in an increase in the hardness and darkening of the cookies while reducing their volume.

Chemical Composition, Antioxidant Activity and Cytocompatibility of Polyphenolic Compounds Extracted from Food Industry Apple Waste: Potential in Biomedical Application

Apple pomace (AP) from the food industry is a mixture of different fractions containing bioactive polyphenolic compounds. This study provides a systematic approach toward the recovery and evaluation of the physiochemical and biological properties of polyphenolic compounds from AP. We studied subcritical water extraction (SCW) and solvent extraction with ethanol from four different AP fractions of pulp, peel, seed, core, and stem (A), peel (B), seed and core (C), and pulp and peel (D). The subcritical water method at the optimum condition resulted in total polyphenolic compounds (TPC) of 39.08 ± 1.10 mg GAE per g of AP on a dry basis compared to the ethanol extraction with TPC content of 10.78 ± 0.94 mg GAE/g db. Phloridzin, chlorogenic acid, and quercetin were the main identified polyphenolics in the AP fractions using HPLC. DPPH radical scavenging activity of fraction B and subcritical water (SW) extracts showed comparable activity to ascorbic acid while all ethanolic extracts were cytocompatible toward human fibroblast (3T3-L1) and salivary gland acinar cells (NS-SV-AC). Our results indicated that AP is a rich source of polyphenolics with the potential for biomedical applications.

Polysaccharides from apple pomace exhibit anti-fatigue activity through increasing glycogen content

The polysaccharides were isolated from apple pomace by hot-water extraction, and their anti-fatigue activity was evaluated in C2C12 muscle myoblasts and male Kunming mice. The purified polysaccharides from apple pomace (PAP) have a molecular weight of 1.74 × 105 Da and were composed of mannose, rhamnose, glucose, galactose and arabinose. In C2C12 myoblasts, PAP showed no cytotoxicity in the concentrations of 0-300 μg/ml. PAP treatment increased the glycogen content, while the ATP content was not affected in C2C12 myoblasts. Further investigation found that the activity and gene expression of glycogen synthase, rather than glycogen phosphorylase, were upregulated by PAP treatment. The studies in vivo showed that PAP treatment did not affect the food intake and weight again in mice. Importantly, PAP prolonged the exhaustive swimming time, increased hepatic and skeletal muscle glycogen levels, and effectively inhibited the accumulation of blood lactic and blood urea nitrogen in mice. Taken together, the results suggested that PAP exhibit anti-fatigue activity in vitro and in vivo through increasing glycogen content.

Impact of Apple Pomace Powder on the Bioactivity, and the Sensory and Textural Characteristics of Yogurt

This study focused on the development of a yogurt with an improved structure, texture and antioxidant activity level, by using apple pomace (AP) powder that was obtained in large quantities during the production of juices. The objective was to determine the sensory, physicochemical, textural and antioxidant characteristics of yogurt with the addition of AP powder (0.2-1.0%), during its shelf life. The physicochemical composition of AP was determined as follows: dietary fibers-62.73%, including pectin-23.12%; and the content of the antioxidant compounds in AP-total polyphenols (728.8 mg GAE/100 g DW), flavonoids (246.5 mg QE/100 g DW), tannins (63.54 mg TAE/100 g DW), carotenoids (4.93 mg/100 g DW) and the ability to inhibit the free radical (2433 µmol TE/100 g DW). AP addition reduces the yogurt fermentation time. The increase in the total dietary fiber content of up to 0.63% and in the insoluble fiber of up to 0.14% was attested in this study, as well as a significant increase in antioxidant activity, which correlated to the AP content. The addition of AP improved the textural properties of the yogurt during storage (20 days) and led to a significant reduction in syneresis. The influence of the AP content and the storage period on the textural characteristics and the overall acceptability of the yogurt samples were analyzed by the mutual information method. The AP content greatly influenced the yogurt's quality, with the information analysis value for the overall acceptability being 0.965 bits. The analysis of the sensory and textural parameters of the yogurt during storage (1-20 days) demonstrated that samples with AP in proportions of 0.6-0.8% were evaluated with the highest score.

Sustainable Approaches Using Green Technologies for Apple By-Product Valorisation as A New Perspective into the History of the Apple

The apple has been recognised as the most culturally important fruit crop in temperate land areas. Centuries of human exploitation and development led to the production of thousands of apple cultivars. Nowadays, the apple represents the third most widely cultivated fruit in the world. About 30% of the total production of apples is processed, being juice and cider the main resulting products. Regarding this procedure, a large quantity of apple by-product is generated, which tends to be undervalued, and commonly remains underutilised, landfilled, or incinerated. However, apple by-product is a proven source of bioactive compounds, namely dietary fibre, fatty acids, triterpenes, or polyphenols. Therefore, the application of green technologies should be considered in order to improve the functionality of apple by-product while promoting its use as the raw material of a novel product line. The present work provides a holistic view of the apple’s historical evolution, characterises apple by-product, and reviews the application of green technologies for improving its functionality. These sustainable procedures can enable the transformation of this perishable material into a novel ingredient opening up new prospects for the apple’s potential use and consumption.

Apple Pomace as Valuable Food Ingredient for Enhancing Nutritional and Antioxidant Properties of Italian Salami

Nowadays, food fortification with bioactive compounds deriving from agri-food waste is of great interest all over the world. In this work, apple pomace (AP), the most abundant by-product of apple juice manufacturing, was characterised by chemical, chromatographic and spectrophotometric analyses. AP showed valuable antioxidant activity, due to the presence of phenolic compounds (8.56 mg gallic acid equivalents/g), including quercetin-3-O-galactoside, quercetin-3-O-arabinofuranoside, and phloridzin. Dried AP, at 7% and 14%, was added to pork meat to produce Italian salami, then subjected to 25 days of ripening. Physicochemical, colorimetric and microbiological analyses were carried out at days 0, 5, 11, 19 and 25, while nutritional and sensory evaluations were performed at the end of the ripening. The overall acceptability was slightly higher for 7% AP compared to 14% AP sample, and generally the replacement of a percentage of meat with apple pomace allowed the production of salami with sensory properties comparable to those obtained with classic recipes. The improved fibre and phenol content, together with the lower fat and calories, represent the most interesting characteristics of fortified salami. The results confirm that the addition of AP represents a valid approach to adding healthy compounds to salami.

Fruit Juice Industry Wastes as a Source of Bioactives

Food processing sustainability, as well as waste minimization, are key concerns for the modern food industry. A significant amount of waste is generated by the fruit juice industry each year. In addition to the economic losses caused by the removal of these wastes, its impact on the environment is undeniable. Therefore, researchers have focused on recovering the bioactive components from fruit juice processing, in which a great number of phytochemicals still exist in the agro-industrial wastes, to help minimize the waste burden as well as provide new sources of bioactive compounds, which are believed to be protective agents against certain diseases such as cardiovascular diseases, cancer, and diabetes. Although these wastes contain non-negligible amounts of bioactive compounds, information on the utilization of these byproducts in functional ingredient/food production and their impact on the sensory quality of food products is still scarce. In this regard, this review summarizes the most recent literature on bioactive compounds present in the wastes of apple, citrus fruits, berries, stoned fruits, melons, and tropical fruit juices, together with their extraction techniques and valorization approaches. Besides, on the one hand, examples of different current food applications with the use of these wastes are provided. On the other hand, the challenges with respect to economic, sensory, and safety issues are also discussed.

Fruit pomaces-their nutrient and bioactive components, effects on growth and health of poultry species, and possible optimization techniques

The ever-growing human population, coupled with the exigent need to meet the increasing demand for poultry meat and egg, has put the onus on poultry nutritionists and farmers to identify alternative feed ingredients that could assure the least-cost feed formulation. In addition, the public desire for non-antibiotic-treated poultry products has also necessitated the ultimate search for potent antibiotic alternatives for use in poultry production. While some identified alternatives are promising, their cost implications and technical know-how requirements may discourage their ease of adoption in poultry. The use of plants and/or their by-products, like fruit pomaces, present a pocket-friendly advantage and as a result, are gaining much interest. This is traceable to their rich phytochemical profile, nutritional composition, ready availability, and relatively cheap cost. The fruit juice and wine pressing industries generate a plethora of fruit wastes annually. Interestingly, fruit pomaces contain appreciable dietary fibre, protein, and phenolic compounds, and thus, their adoption could serve the poultry industry in dual capacities including as substitutes to antibiotics and some conventional feedstuff. Thus, there is a possibility to reduce fruit wastes produced and feed-cost in poultry farming from environmental and economical standpoints, respectively. This review seeks to provide reinforcing evidence on the applicability and impact of fruit pomaces in poultry nutrition.

Utilization of Fruit Seed-Based Bioactive Compounds for Formulating the Nutraceuticals and Functional Food: A Review

Fruit seeds include a large number of bioactive substances with potential applications in the culinary and pharmaceutical industries, satisfying current demands for natural ingredients, which are generally preferred since they have fewer adverse effects than artificial components. Researchers have long been interested in the functional features, as well as the proximate and mineral compositions, of diverse fruit seeds such as tomato, apple, guava, and dates, among others. Bioactive components such as proteins (bioactive peptides), carotenoids (lycopene), polysaccharides (pectin), phytochemicals (flavonoids), and vitamins (-tocopherol) are abundant in fruit by-products and have significant health benefits, making them a viable alternative for the formulation of a wide range of food products with significant functional and nutraceutical potential. This article discusses the role and activities of bioactive chemicals found in tomato, apple, dates, and guava seeds, which can be used in a variety of food forms to cure a variety of cardiovascular and neurological disorders, as well as act as an antioxidant, anticancer, and antibacterial agent. The extraction of diverse bioactive components from by-products could pave the path for the creation of value-added products from the fruit industry, making it more commercially viable while also reducing environmental pollution caused by by-products from the fruit industry.

Selected Physico-Chemical, Nutritional, Antioxidant and Sensory Properties of Wheat Bread Supplemented with Apple Pomace Powder as a By-Product from Juice Production

The present article aimed to study the effects of four selected concentrations (1%, 2%, 5%, and 10%) of apple pomace powder (APP), obtained from juice production, on the nutritional value and selected physico-chemical, antioxidant, and sensory properties of wheat bread. We have found that the ash and total carbohydrate contents, total polyphenols content, and antioxidant activity of the supplemented bread loaves were markedly higher (p < 0.05) as compared to the control ones. On the other hand, values for protein and fat contents and loaf volume in APP-containing bread samples were statistically lower (p < 0.05). Finally, sensory evaluation revealed no significant differences in all tested attributes between the investigated groups of bread samples. The current results suggest that 10% APP addition appears to be an attractive ingredient applied to bread formulation to obtain a bakery product with high nutritional value and required qualitative and sensory properties. In such a manner, apple pomace as by-products from apple juice processing can be efficiently utilized in an eco-friendly way by the food industry to decrease unnecessary waste and environmental pollution.

Technology for Apple Pomace Utilization within a Sustainable Development Policy Framework

The aim of this study was to develop a concept, within the framework of sustainable agriculture, for utilizing apple pomace as a valuable raw material in food production. The proposal includes a description of the production technology of four food products together with the characteristics of their chemical composition, wholesome compounds, and physical properties. These new products were developed on the basis of apple pomace and wheat bran. In the developed technology, heat treatment in a convection oven, treatment with infrared radiation, and two types of barothermic treatments, i.e., extrusion and granulation, were implemented as the principal methods. All of the proposed technologies allow for the use of pomace for the production of food products to be made directly in the home plant and are relatively easy to implement in small processing facilities. It was found that the product consisting of fragmented apple pomace (mass fraction: 75%) and wheat bran (mass fraction: 25%), obtained using infrared radiation treatment, had the greatest value in terms of wholesome characteristics among the products obtained. This product had high contents of fiber and simple sugars, the highest content of polyphenols among the obtained products, and the ability to scavenge free radicals. It was also the only one with partially preserved vitamin C. The proposed method for processing pomace for food is in line with the sustainable agriculture movement.

Agricultural crop waste materials - A potential reservoir of molecules

Crop wastes are one of the agricultural wastes generated during the production and processing of food materials. Their generation is the other side of developmental activities. They are now becoming an alarming source of environmental pollution, leading to an unhealthy society. There is an urgent need to develop robust methods to utilize these types of wastes into beneficial compounds or materials. Many works are successfully done in these areas, and several strategies have been developed to produce biochemicals from biological wastes. In other words, value addition has been done to the crop waste materials. The chemicals like carbohydrates, minerals, proteins, and other compounds have been isolated from various crop residues. In this context, this article covers an overview of the crop wastes, chemicals isolated from them, their extraction methods, and the way forward to get the valuable chemicals.

Dietary fiber in bakery products: Source, processing, and function

Bakery products are prevalently consumed foods in the world, and they have been regarded as convenient dietary vehicles for delivering nutritive ingredients into people's diet, of which, dietary fiber (DF) is one of the most popular items. The food industry attempts to produce fiber-enriched bakery products with both increasing nutritional value and appealing palatability. As many new sources of DFs become available, and consumers are moving towards healthier diets, studies of using these DFs as functional ingredients in baked goods are becoming vast. Besides, the nutrition value of DF is commonly accepted, and many investigations have also revealed the health benefits of fiber-enriched bakery products. Thus, this chapter presents an overview of (1) trends in supplementation of DF from various sources, (2) impact of DF on dough processing, quality and physiological functionality of bakery products, and (3) technologies used to improve the compatibility of DF in bakery products.

The ability of deep eutectic solvent systems to extract bioactive compounds from apple pomace

The objective of this study was to examine the bioactivity of extracts from apple pomace obtained by non-conventional green extraction methods (DES systems). Bioactivity was antioxidant capacity and ability to stimulate insulin secretion from pancreatic beta-cells. The antioxidant capacity of extracts was examined using the DPPH and the FRAP assay. Impact of the extracts on cell viability and insulin secretion were examined using the BRIN-BD11 cell line. ChCl:EG(1:4) extracts resulted in high antioxidant capacity in the DPPH assay (80.1% inhibition versus 11.3%). Extracts obtained from the classical systems demonstrated an ability to promote insulin secretion significantly higher than the positive control, p < 0.05. ChCl:EG(1:4) extracts stimulated insulin secretion to a lesser extent. Overall, the data provides evidence for the potential of DES systems to extract bioactive compounds from apple pomace that have relevance for metabolic health. Further optimisation of the extraction procedures should be tailored to the desired bioactive properties.

Analysis of Fatty Acids, Amino Acids and Volatile Profile of Apple By-Products by Gas Chromatography-Mass Spectrometry

Apple industrial by-products are a promising source of bioactive compounds with direct implications on human health. The main goal of the present work was to characterize the Jonathan and Golden Delicious by-products from their fatty acid, amino acid, and volatile aroma compounds’ point of view. GC-MS (gas chromatography-mass spectrometry) and ITEX/GC-MS methods were used for the by-products characterization. Linoleic and oleic were the main fatty acids identified in all samples, while palmitic and stearic acid were the representant of saturated ones. With respect to amino acids, from the essential group, isoleucine was the majority compound identified in JS (Jonathan skin) and GS (Golden skin) samples, lysine was the representant of JP (Jonathan pomace), and valine was mainly identified in GP (Golden pomace). A total number of 47 aroma volatile compounds were quantified in all samples, from which the esters groups ranged from 41.55–53.29%, aldehydes 29.75–43.99%, alcohols from 4.15 to 6.37%, ketones 4.14–5.72%, and the terpenes and terpenoids group reached values between 2.27% and 4.61%. Moreover, the by-products were valorized in biscuits manufacturing, highlighting their importance in enhancing the volatile aroma compounds, color, and sensorial analysis of the final baked goods.

Sustainable Use of Apple Pomace (AP) in Different Industrial Sectors

In many countries, apple pomace (AP) is one of the most produced types of agri-food waste (globally, it is produced at a rate of ~4 million tons/year). If not managed properly, such bio-organic waste can cause serious pollution of the natural environment and public health hazards, mainly due to the risk of microbial contamination. This review shows that AP can be successfully reused in different industrial sectors—for example, as a source of energy and bio-materials—according to the idea of sustainable development. The recovered active compounds from AP can be applied as preservatives, antioxidants, anti-corrosion agents, wood protectors or biopolymers. Raw or processed forms of AP can also be considered as feedstocks for various bioenergy applications such as the production of intermediate bioenergy carriers (e.g., biogas and pyrolysis oil), and materials (e.g., biochar and activated carbon). In the future, AP and its active ingredients can be of great use due to their non-toxicity, biodegradability and biocompatibility. Given the increasing mass of produced AP, the commercial applications of AP could have a huge economic impact in the future.

Apple Pomace as a Sustainable Substrate in Sourdough Fermentation

Innovations range from food production, land use, and emissions all the way to improved diets and waste management. Global apple production has amounted to over 87 million tons/year, while 18% are processed, resulting in 20-35% (apple fruit fresh weight) apple pomace (AP). Using modern AP management, integrated knowledge in innovative fermentation demonstrates opportunities for reducing environmental pollution and integration into a circular economy. With this association in view, integrating AP flour during sourdough fermentation increases the nutritional value, highlighting a new approach that could guide innovative fermented foods. In this study, the wheat flour (WF) and AP flour were mixed at different ratios, hydrated with water (1:1 w/v), and fermented using a selective culture of Fructilactobacillus florum DSM 22689 and baker's yeast (single and co-culture). Sourdough fermentation was monitored and analyzed for 72 h. Results suggested that AP may be an important source of organic acids and fermentable sugars that increase nutritional sourdough value. AP flour addition in WF had a positive effect, especially in fermentations with 95% WF and 5% AP, mainly in co-culture fermentation.

Kinetic modelling of the solid-liquid extraction process of polyphenolic compounds from apple pomace: influence of solvent composition and temperature

This study aims to assess kinetic modelling of the solid-liquid extraction process of total polyphenolic compounds (TPC) from apple pomace (AP). In this regard, we investigated the effects of temperature and solvent (i.e. water, ethanol, and acetone) on TPC extraction over various periods. The highest TPC yield of 11.1 ± 0.49 mg gallic acid equivalent (GAE)/g db (dry basis) was achieved with a mixture of 65% acetone-35% water (v/v) at 60 °C. The kinetics of the solvent-based TPC extraction processes were assessed via first-order and second-order kinetic models, with an associated investigation of the kinetic parameters and rate constants, saturation concentrations, and activation energies. The second-order kinetic model was sufficient to describe the extraction mechanism of TPC from AP. This study provides an understanding of the mass transfer mechanism involved in the polyphenolic compound extraction process, thus facilitating future large-scale design, optimization, and process control to valorize pomace waste.

Assessing the Fatty Acid, Carotenoid, and Tocopherol Compositions of Seeds from Apple Cultivars (Malus domestica Borkh.) Grown in Norway

Apple production generates large amounts of apple pomace including seeds, leading to high transportation costs, public health hazards and undesirable odor. A new reuse strategy of this kind of waste could solve environmental issues and/or create unconventional sources of health beneficial products. In total, seeds from 75 apple cultivars grown in Norway (both domestic and international) have been analyzed for the first time for oil content and fatty acid profile together with tocopherols and carotenoids quantification in defatted seeds. Seeds from cultivar Håkonseple had the highest oil content (22.10%), with linoleic, oleic acid, and palmitic acid as the most abundant fatty acids. The levels of β-carotene and lycopene carotenoids and α-tocopherol were the highest in defatted seeds of the cultivar Sureple Grøn. Principal component analysis separated cultivars according to the total oil content. The Norwegian apple cultivars Håkonseple, Kviteple, Tolleivseple, Vinterrosenstrips, and Tokheimseple are recommended for obtaining vegetable oil due to their high oil contents, while cultivar Sureple Grøn can be separated due to its high levels of β-carotene, lycopene and total tocopherols.

Chemical and Bioactive Characterization of Spanish and Belgian Apple Pomace for Its Potential Use as a Novel Dermocosmetic Formulation

Currently, there is a general trend towards reutilizing industrial by-products that would otherwise be discarded or considered as waste, aiming to explore them as alternative sources of valuable compounds. The apple pomace remaining from cider and apple juice industries represents a high-potential source of bioactive compounds with putative application in food or pharmaceutical-related products. Accordingly, the work reported herein was conducted to characterize the phenolic compounds in apple pomace from Belgium and Spain, as well as to evaluate its chemical composition and particular types of bioactivity. As a proof of concept, a new hydrogel was prepared, incorporated with the bioactive compounds and pectin extracted from apple pomace, aiming to obtain the most organic formulation possible. Independently of the extracting agent, it became evident that using lyophilization as the drying step is a better choice than thermal processes as it yielded a richer phenolic profile (fifteen individual compounds), with 5-O-caffeoylquinic acid as the major compound (66 to 114 mg/100 g dw) in Belgian samples. In general, the hydroethanolic extracts showed the strongest antioxidant and antimicrobial (particularly against Propionibacterium acnes: MIC = 2.5 mg/mL) activities. This result, together with the lipid nature of human skin, led it to be chosen as the extract type to be incorporated in the hydrogel. In general, apple pomace stood out as a valuable source of bioactive compounds, especially polyphenols and pectin, with good potential to be incorporated in dermal formulations.

Berry fruits as source of pectin: Conventional and non-conventional extraction techniques

Three non-conventional extraction techniques (enzyme-assisted with cellulase, citric acid ultrasound-assisted and enzyme-ultrasound-assisted treatment) and conventional citric acid extraction were applied to obtain pectin from raspberry, blueberry, strawberry and redcurrant, and were compared in terms of extraction yields and physicochemical properties of the extracted pectins. Except for pectin from raspberry, conventional citric acid extraction led to the highest extraction yield (~8%) and, for the same berries, the lowest pectin recovery was found for the extraction with cellulase (~4%). Regarding the structural characteristics of pectins, enzymatically extracted pectins from redcurrant and strawberry exhibited the highest levels of galacturonic acid (≥73%) whereas, in general, this monosaccharide was found from 51 to 69% in the rest of samples. Although, ultrasound-assisted extraction did not improve pectin yield, it minimized the levels of "non-pectic" components leading to the obtainment of purer pectin. The different monomeric composition and the wide range of molecular weight of the obtained pectins pointed out their usefulness in different potential food applications (e.g., thickening, gelling ingredients) and biological activities. This has been evidenced by the differences found in their physicochemical and techno-functional characteristics. Finally, it can be considered that the berries here studied are efficient sources of pectin.