Optimization of lactic acid production from apple and tomato pomaces by thermotolerant bacteria.

The production of lactic acid (LA) through biomass fermentation represents a promising alternative to the chemical synthesis. The use of agri-food by-products as fermentable carbohydrate sources can improve process sustainability by reducing waste and valorizing residual biomass. This study assessed the use of apple and tomato pomaces for producing LA through fermentation using thermotolerant bacteria under aerobic and non-sterile conditions. Three bacteria were evaluated and Heyndrickxia coagulans DSM 2314 was selected for its ability to produce LA from hydrolyzates of apple pomace (APH) and tomato pomace (TPH). The fermentation conditions were optimized to maximize LA production from APH, TPH and a mixture of both hydrolyzates. Therefore, LA productions ranged from 36.98 ± 0.41 to 40.72 ± 0.43 g/L, with yields from 0.86 ± 0.02 to 1.01 ± 0.01 g/g. Yeast extract was necessary as a nitrogen source for fermenting APH, while TPH and the mixture of both hydrolyzates did not require any supplementation. Other nitrogen sources, such as wine lees, urea and NH3Cl, were tested for fermenting APH. However, mixing this hydrolyzate with TPH proved to be the most viable alternative. This study demonstrates the potential for valorizing apple and tomato pomaces into LA under feasible fermentation conditions.

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.

Performance and nutrient digestibility of growing pigs fed highly or low fermentable coarse or finely ground fibre-rich feedstuffs.

Dietary fibre is mainly classified according to its chemical characteristics but structure and particle size of fibre-rich feedstuff can also be decisive for digestion and performance. So far, only few studies investigated this in pigs. This experiment aimed to compare coarse and finely ground dried hemp plants and apple pomace regarding performance and ileal and total tract nutrient digestibility of growing pigs. Coarse or finely ground apple pomace or dried hemp plants were added to the diet of 56 nine weeks old growing pigs (DanBred x Duroc), housed in flat decks with each 2 animals. The growing pigs received the experimental diets for three weeks while performance was recorded. Eight pigs per group were sacrificed and digesta and organ tissue sampled. The stomach health was evaluated by visually scoring of the mucosa integrity. Apparent ileal (AID) and total tract digestibility (ATTD) were calculated using titanium dioxide as marker. Statistical analyses were performed using two-way ANOVA (p < 0.05). The highest feed intake (fibre particle size, p = 0.018) and bodyweight gain (fibre particle size, p = 0.018; fibre source x particle size interaction, p = 0.040), was observed in animals fed finely ground apple pomace, while the feed conversion ratio was 8-12% lower in pigs fed finely ground fibre sources (p = 0.012). No differences in stomach mucosa integrity were detected between the groups. The relative pancreas (p = 0.045), stomach (p < 0.001), and jejunum (p = 0.010) weights were higher in animals fed diets containing apple pomace. In contrast, the relative liver, caecum and colon weights were not affected by fibre source or particle size. The AID of protein and amino acids was not affected, while ATTD was increased by fibre source (hemp vs. apple pomace) reducing faecal nitrogen excretion. The AID of calcium was increased when diets contained apple pomace (p < 0.001), while zinc AID and ATTD were enhanced when diets contained dried hemp (p = 0.016; p = 0.016, respectively). Our results suggest that the structure as well as the chemical characteristics should be considered in a future fibre evaluation system in pigs.

Apple Pomace Extract Induces Cell Proliferation and Increases Type I Collagen and Hyaluronan Production in Human Skin Fibroblasts In Vitro.

Apple pomace is the residue left after apples are squeezed. The majority of pomace produced worldwide is produced by the apple manufacturing industry, however, most of the pomace produced by the industry is discarded. Apple pomace contains functional ingredients, such as polyphenols and triterpenoids, and exerts several beneficial effects on human health; however, studies on its cosmetic effects on the skin are lacking. Therefore, herein, we investigated the effects of apple pomace extract (APE) on human skin fibroblasts (HSFs) in vitro. When HSFs were cultured with the extract for 72 h, the number of HSFs increased at concentrations of 10 and 20 µg/mL. Transcriptome analysis and reverse transcription-quantitative PCR results revealed that the extract upregulated the expression of hyaluronan synthase (HAS) 1, HAS2, and HAS3 and downregulated the expression of HYAL1, a gene encoding the hyaluronan-degrading enzyme, in HSFs. Additionally, enzyme-linked immunosorbent assay revealed increased amounts of factors related to skin extracellular matrix, such as type I collagen and hyaluronic acid, secreted in the culture supernatant. The western blotting results suggested that the extract induced extracellular signal-regulated kinase and protein kinase B phosphorylation in HSFs. Additionally, several GO_Terms related to mitosis were detected in the Gene Ontology analysis. This is the first study to show that APE induces the proliferation of HSFs and production of factors related to skin anti-aging.

Understanding consumer preferences to develop dahi using pineapple pomace powder and monk-fruit extract.

Consumer preferences refer to the subjective assessments of products and services expressed by individuals. The objective of this investigation aims to examine the preferences of consumers regarding dahi, followed by the development of a corresponding product. The initial phase of the experimental design involves understanding the interests of consumers and the variables that influence their purchasing intentions through the administration of a questionnaire. The subsequent phase entails the development of dahi in accordance with consumer preferences, followed by an assessment of its nutritional value, sensory acceptability, and storage study. Subsequently, a significant proportion of consumers (91%) expressed an interest for the introduction of a pineapple-flavour (61.5%) spoon-able dahi (77%) containing natural sugar (65%) and packaged in a cup (71.5%) within the market. To adjust the sweetness intensity of monk fruit, a series of preliminary experiments were carried out to regulate the concentration to a level that can be considered sensory acceptable, specifically 05 g/100 ml. Afterwards, dahi was prepared by altering the concentration of FPP (freeze-dried pine-apple pomace powder) within the range of 0.5 to 2.5 g/100 ml. Prepared dahi were further subjected to sensory evaluation and storage study. Based on the obtained results and sensory analyst feedback, we conclude that the dahi formulation TPM2 exhibits considerable organoleptic acceptance and also has the potential for industrial-scale production to cater wider consumer demands. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05919-5.

A review of the polyphenols extraction from apple pomace: novel technologies and techniques of cell disintegration.

Apple pomace, a solid waste produced during industrial processing of apple juice or cider, is a rich source of high value-added compounds such as polyphenols. This review summarizes present studies on the qualitative and quantitative methods, including Folin-Ciocalteu colorimetric, high pressure liquid chromatography (HPLC) and fluorescence spectrum, as well as enhanced extraction methods of polyphenols in apple pomace by different traditional and novel technologies, including ultrasounds (US), microwave (MW), pulsed electric fields (PEF), high voltage electrical discharges (HVED) and enzyme. The principles and characteristics of different effective enhanced extraction technologies of polyphenols in apple pomace were compared. In addition, the different cell disruption analysis methods, such as destructive detection method (electrical conductivity disintegration index, Zc), image analysis method (including scanning electron microscopy, SEM, and confocal laser scanning microscopy, CLSM), and nondestructive method (such as magnetic resonance imaging, MRI) are presented in this review. The study proved that there was a correlation between destructive detection method and image analysis method. However, each of the technologies reviewed in this study has some disadvantages to overcome, and some mechanisms need to be further substantiated. Therefore, more competitive techniques for polyphenols extraction and analysis of cell disintegration are needed to emerge in the future.

RNA-sequencing revealed apple pomace ameliorates expression of genes in the hypothalamus associated with neurodegeneration in female rats fed a Western diet during adolescence to adulthood.

OBJECTIVES: Apple pomace, a waste byproduct of apple processing, is rich in nutrients (e.g. polyphenols and soluble fiber) with the potential to be neuroprotective. The aim of this study was to employ RNA-sequencing (RNASeq) technology to investigate diet-gene interactions in the hypothalamus of rats after feeding a Western diet calorically substituted with apple pomace. METHODS: Adolescent (age 21-29 days) female Sprague-Dawley rats were randomly assigned (n = 8 rats/group) to consume either a purified standard diet, Western (WE) diet, or Western diet calorically substituted with 10% apple pomace (WE/AP) for 8 weeks. RNA-seq was performed (n = 5 rats/group) to determine global differentially expressed genes in the hypothalamus. RESULTS: RNA-seq results comparing rats fed WE to WE/AP revealed 15 differentially expressed genes in the hypothalamus. Caloric substitution of WE diet with 10% apple pomace downregulated (q < 0.06) five genes implicated in brain aging and neurodegenerative disorders: synuclein alpha, phospholipase D family member 5, NADH dehydrogenase Fe-S protein 6, choline O-acetyltransferase, and frizzled class receptor 6. DISCUSSION: Altered gene expression of these five genes suggests that apple pomace ameliorated synthesis of the neurotransmitter, acetylcholine, in rats fed a WE diet. Apple pomace, a rich source of antioxidant polyphenols and soluble fiber, has been shown to reverse nonalcoholic fatty liver disease (NAFLD). Diet-induced NAFLD decreases hepatic de novo synthesis of choline, a precursor to acetylcholine. Based on preclinical evidence, apple pomace has the potential to be a sustainable functional food for maintaining brain function and for reducing the risk of neurodegeneration.

Synthesis of 2'-fucosyllactose from apple pomace-derived xyloglucan oligosaccharides by an α-L-fucosidase from Pedobacter sp. CAU209.

2'-Fucosyllactose (2'-FL) is known for its ability to provide various health benefits to infants, such as gut maturation, pathogen resistance, improved immunity, and nervous system development. However, the production of 2'-FL using α-L-fucosidases is hindered by the lack of low-cost natural fucosyl donors and high-efficiency α-L-fucosidases. In this work, a recombinant xyloglucanase from Rhizomucor miehei (RmXEG12A) was applied to produce xyloglucan-oligosaccharide (XyG-oligos) from apple pomace. Then, an α-L-fucosidase gene (PbFucB) was screened from the genomic DNA of Pedobacter sp. CAU209 and expressed in Escherichia coli. The capability of purified PbFucB to catalyze XyG-oligos and lactose to synthesize 2'-FL was further evaluated. The deduced amino acid sequence of PbFucB shared the highest identity (38.4%) with that of other reported α-L-fucosidases. PbFucB showed the highest activity at pH 5.5 and 35 °C. It catalyzed the hydrolysis of 4-nitrophenyl-α-L-fucopyranoside (pNP-Fuc, 20.3 U mg-1), 2'-FL (8.06 U mg-1), and XyG-oligos (0.43 U mg-1). Furthermore, PbFucB demonstrated a high enzymatic conversion rate in 2'-FL synthesis with pNP-Fuc or apple pomace-derived XyG-oligos as donors and lactose as acceptor. Under the optimized conditions, PbFucB converted 50% of pNP-Fuc or 31% of the L-fucosyl residue in XyG-oligos into 2'-FL. This work elucidated an α-L-fucosidase that mediates the fucosylation of lactose and provided an efficient enzymatic strategy to synthesize 2'-FL either from artificial pNP-Fuc or natural apple pomace-derived XyG-oligos. KEY POINTS: • Xyloglucan-oligosaccharide (XyG-oligos) was produced from apple pomace by a xyloglucanase from Rhizomucor miehei. • An α-L-fucosidase (PbFucB) from Pedobacter sp. CAU209 shared the highest identity (38.4%) with reported α-L-fucosidases. •PbFucB synthesized 2'-FL using apple pomace-derived XyG-oligos and lactose with a conversion ratio of 31%.

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.

In vitro anti-obesity activity by pancreatic lipase inhibition - Simple HPLC approach using EVOO as natural substrate.

BACKGROUND: Pancreatic lipase (PL) is a key lipolytic enzyme in humans for the digestion and absorption of dietary fats. Thereby, PL is a well-recognized target in the management of obesity and its inhibition attracts the interest of researchers globally. The screening of new natural PL inhibitors as alternative strategy to the synthesis of chemical ones represents nowadays a hot topic in research. The main challenge in this matter is the lack of a universal analytical method allowing the monitoring of PL activity and the reliable quantification of lipid digestion products. RESULTS: The (normal phase)-high-performance liquid chromatography-evaporative light scattering detector [(NP)-HPLC-ELSD] method proposed in this work represents a direct and rapid strategy to simultaneously quantify the products obtained from in vitro PL digestion. As one of the main novelties, the triacylglycerol (TAG) fraction from extra-virgin olive oil was selected as natural substrate. The PL activity was measured by monitoring the levels of remaining TAGs and formed free fatty acids (FFAs), using Orlistat as known inhibitor. The method validation confirmed the adequacy of the analytical method for quantitative purposes, showing high recovery percentage values (between 99% and 103%) and low relative standard deviation (RSD%) values (between 2% and 7%) for triolein and oleic acid standard solutions, as well as appreciably low limit of detection (LOD) and limit of quantification (LOQ) values (respectively 58 and 177 ng mL-1 for triolein; 198 and 602 ng mL-1 for oleic acid). Finally, the developed HPLC-ELSD method was successfully applied to evaluate the inhibitory effect of a polyphenolic extract obtained from apple pomace. The results showed a comparable inhibition degree between a 4.0 mg mL-1 apple pomace solution and a 1.0 µg mL-1 Orlistat solution. CONCLUSION: The proposed innovative method reveals highly sensitive and simple to follow the fate of PL digestion, thus opening the way to further investigations in the research of new potentially anti-obesity compounds. © 2022 Society of Chemical Industry.

Effects of wet brewers grains on fermentation quality and in vitro ruminal digestibility of mixed silage prepared with corn stalk, sweet potato peel and dried apple pomace in southeast China.

The effects of wet brewers grains (WBG) on fermentation quality, chemical composition and in vitro ruminal digestibility of mixed silages prepared with corn stalk, dried apple pomace and sweet potato peel were evaluated. A mixture of corn stalk, sweet potato peel and dried apple pomace (50/30/20) was ensiled with 0, 10%, 20% and 30% WBG on a fresh weight (FW) basis for 1, 3, 5, 7, 14 and 30 days respectively. The results showed that the application of WBG increased (p < 0.05) lactic acid, acetic acid and total volatile fatty acids contents, and decreased (p < 0.05) pH, dry matter, water-soluble carbohydrates content and ammonia-nitrogen/total nitrogen during ensiling. The pH in all silages was below 4.03 during ensiling. Treating with WBG increased (p < 0.05) crude protein content, and decreased (p < 0.05) neutral detergent fibre, acid detergent fibre, cellulose and hemicellulose content after 30 days of ensiling. After 72 h of incubation, cumulative gas production, potential gas production and in vitro crude protein digestibility increased (p < 0.05) with the increasing proportions of WBG. However, in vitro digestibility of dry matter and neutral detergent fibre, and metabolisable energy were similar in all silages. The 20% and 30% WBG-treated silages showed better fermentation quality and greater or higher in vitro digestibility, which were indicated by greater or higher (p < 0.05) lactic acid content, in vitro crude protein digestibility, and lower (p < 0.05) pH, ammonia-nitrogen/total nitrogen ratio as compared with the control. Therefore, ensiling agro-food by-products with at least 20% WBG were recommended for improving fermentation quality.

Influence of Enzymatic Hydrolysis on Composition and Technological Properties of Apple Pomace and Its Application for Wheat Bread Making.

The aim of this work was to evaluate the influence of enzymatic hydrolysis on dietary fiber, phenolic compounds and technological properties of apple pomace as wheat bread supplement. Apple pomace was hydrolyzed with Viscozyme® L, Pectinex® Ultra Tropical, Celluclast® 1.5 L for 1 and 5 h. Soluble (SDF) and insoluble (IDF) dietary fiber, reducing sugars and the total phenolic contents (TPC), along with the technological properties (water and oil retention capacities, solubility index, emulsion stability) of treated apple pomace were evaluated. The prebiotic activity of apple pomace water-soluble fraction on two probiotic strains Lactobacillus acidophilus DSM 20079 and Bifidobacterium animalis DSM 20105 was investigated. Treatment with Celluclast® 1.5 L increased SDF, reducing sugars, SDF/IDF ratio and decreased IDF of apple pomace. While treatment with Viscozyme® L, Pectinex® Ultra Tropical increased reducing sugars, solubility index and TPC, but in most cases reduced oil and water retention capacities, decreased SDF and IDF content. All apple pomace extracts promoted growth of probiotic strains. Addition of 5% of apple pomace hydrolyzed with Celluclast® 1.5 L did not have negative impact on wheat bread, while addition of other enzymatically hydrolyzed apple pomaces decreased pH, specific volume and porosity of wheat bread. Obtained results suggest that apple pomace enzymatically hydrolyzed with Celluclast® 1.5 L can be potentially used for wheat bread supplementation with dietary fiber.

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.

Use of apple pomace, glycerine, and potato wastewater for the production of propionic acid and vitamin B12.

Propionic acid bacteria (PAB) are a source of valuable metabolites, including propionic acid and vitamin B12. Propionic acid, a food preservative, is synthesized from petroleum refining by-products, giving rise to ecological concerns. Due to changing food trends, the demand for vitamin B12 has been expected to increase in the future. Therefore, it is necessary to look for new, alternative methods of obtaining these compounds. This study was conducted with an aim of optimizing the production of PAB metabolites using only residues (apple pomace, waste glycerine, and potato wastewater), without any enzymatic or chemical pretreatment and enrichment. Media consisting of one, two, or three industrial side-streams were used for the production of PAB metabolites. The highest production of propionic acid was observed in the medium containing all three residues (8.15 g/L, yield: 0.48 g/g). In the same medium, the highest production of acetic acid was found - 2.31 g/L (0.13 g/g). The presence of waste glycerine in the media had a positive effect on the efficiency of propionic acid production and P/A ratio. The concentration of vitamin B12 obtained in the wet biomass of Propionibacterium freudenreichii DSM 20271 ranged from 90 to 290 µg/100 g. The highest production of cobalamin was achieved in potato wastewater and apple pomace, which may be a source of the precursors of vitamin B12 - cobalt and riboflavin. The results obtained show both propionic acid and vitamin B12 can be produced in a more sustainable manner through the fermentation of residues which are often not properly managed. KEY POINTS: • The tested strain has been showed metabolic activity in the analyzed industrial side-streams (apple pomace, waste glycerine, potato wastewater). • All the side-streams were relevant for the production of propinic acid. • The addition of waste glycerine increases the propionic acid production efficiency and P/A ratio. • B12 was produced the most in the media containing potato wastewater and apple pomace as dominant ingredients.

Effect of Dried Apple Pomace (DAP) as a Feed Additive on Antioxidant System in the Rumen Fluid.

The study aimed to evaluate the effect of dried apple pomace (DAP) as a feed additive on the enzymatic activity and non-enzymatic compounds belonging to the antioxidant system in cattle rumen fluid. The experiment included 4 Polish Holstein−Friesian cannulated dairy cows and lasted 52 days. The control group was fed with the standard diet, while in the experimental group, 6% of the feedstuff was replaced by dried apple pomace. After the feeding period, ruminal fluid was collected. The spectrophotometric technique for the activity of lysosomal enzymes, the content of vitamin C, polyphenols, and the potential to scavenge the free DPPH radical was used. The enzyme immunoassay tests (ELISA) were used to establish the activity of antioxidants enzymes and MDA. Among the rumen aminopeptidases, a significant reduction (p < 0.01) from 164.00 to 142.00 was observed for leucyl-aminopeptidase. The activity of glycosidases was decreased for HEX (from 231.00 to 194.00) and ß-Glu (from 1294.00 to 1136.00), while a significant statistically increase was noticed for BGRD (from 31.10 to 42.40), α-Glu (from 245.00 to 327.00), and MAN (from 29.70 to 36.70). Furthermore, the activity of catalase and GSH (p < 0.01) was inhibited. In turn, the level of vitamin C (from 22.90 to 24.10) and MDA (from 0.36 to 0.45) was statistically higher (p < 0.01). The most positive correlations were observed between AlaAP and LeuAP (r = 0.897) in the aminopeptidases group and between ß-Gal and MAN (r = 0.880) in the glycosidases group. Furthermore, one of the most significant correlations were perceived between SOD and AlaAP (r = 0.505) and AcP (r = 0.450). The most negative correlation was noticed between α-Gal and DPPH (r = −0.533) based on these observations. Apple pomace as a feed additive has an influence on lysosomal degradation processes and modifies oxidation−reduction potential in the rumen fluid. Polyphenols and other low-weight antioxidant compounds are sufficient to maintain redox balance in the rumen.

Ultrasound-Assisted Extraction and Characterization of Polyphenols from Apple Pomace, Functional Ingredients for Beef Burger Fortification.

Currently, there is an increasing interest to valorise agri-food waste containing bioactive compounds with potential health benefits. In this paper, the recovery of functional molecules from apple pomace, the most abundant by-product of the apple processing industry, was carried out by ultrasound-assisted extraction (UAE) on fresh and freeze-dried samples. UAE extract, obtained by double extraction of freeze-dried apple pomace, was subjected to chromatographic and spectrophotometric characterization. It showed good levels of total phenol content, high antioxidant activity, and interesting antioxidant compounds (quercetin derivatives, chlorogenic acid, phloridzin). Subsequently, freeze-dried apple pomace, containing 40.19% of dietary fibre, was used as a fortifying agent for beef burgers (4% and 8%). The results concerning colour and sensory analysis of the fortified products were graded even better than the control (0%). The improved fibre and phenol content, together with the neutral flavour, represent the most interesting characteristics of fortified burgers. The results confirm that UAE was a successful technique for extracting phenol compounds and that the addition of apple pomace represents a valid approach to increase the health properties and palatability of beef burgers, including for consumers who do not like meat.

Quercetin-3-Glucoside Extracted from Apple Pomace Induces Cell Cycle Arrest and Apoptosis by Increasing Intracellular ROS Levels.

Cervical cancer is a life-threatening disease and the fourth most common cancer among women worldwide. Apple pomace is a multifunctional phenolic compound possessing effective biological activity against cervical cancer cells. This study aimed to investigate the anticancer effects of quercetin-3-glucoside (Q3G) extracted from apple pomace in HeLa cell lines and analyze its molecular mechanisms. High-performance liquid chromatography revealed that Q3G, coumaric acid, phloridzin, quercetin, and phloretin are the major polyphenolic compounds constituting apple pomace. Among them, Q3G possessed the greatest antioxidant and anti-inflammatory effects in vitro and exhibited significant cytotoxic effects in HeLa cells in a dose-and time-dependent manner. Flow cytometric analysis indicated that Q3G induced cell cycle arrest at the S phase in a time-dependent manner by altering cyclin-dependent kinase 2. Moreover, it induced apoptosis via chromosomal DNA degradation and increased reactive oxygen species generation. Furthermore, Q3G treatment altered the apoptosis-associated protein expression in the cells by activating caspase-9/-3, downregulating anti-apoptosis protein B-cell lymphoma (Bcl)-2 expressions and up regulating the pro-apoptotic Bcl-2-associated X protein. BH3-interacting domain death agonist cleavage occurred prior to the degradation of an anti-apoptotic Mu-2-related death-inducing gene involved in cell death signaling. Consequently, apple pomace Q3G holds promise as an anti-inflammatory and anticancer agent for treating cervical cancer.

Optimization of Ultrasound Assisted Extraction of Bioactive Compounds from Apple Pomace.

In the present work, the optimization of the extraction of antioxidant compounds from apple pomace using ultrasound technology as an environmentally friendly and intensification process was developed. Different sonication powers, extraction temperatures and extraction times were studied and their influence on extraction yield and characteristics of the extracted samples (total phenolic compounds, flavonoid content and antioxidant capacity) are presented. The elaborated experimental design and the analysis of Pareto and response surface diagrams allowed us to determine the optimal extraction conditions. The conditions that allow the maximum extraction of phenolic compounds were found at 20 min, 90 °C and 50% ultrasound amplitude. Nevertheless, at these conditions, the antioxidant capacity measured by DPPH decreased in the extracted samples.

Use of Propionibacterium freudenreichii T82 Strain for Effective Biosynthesis of Propionic Acid and Trehalose in a Medium with Apple Pomace Extract and Potato Wastewater.

Propionic acid bacteria are the source of many metabolites, e.g., propionic acid and trehalose. Compared to microbiological synthesis, the production of these metabolites by petrochemical means or enzymatic conversion is more profitable. The components of microbiological media account for a large part of the costs associated with propionic fermentation, due to the high nutritional requirements of Propionibacterium. This problem can be overcome by formulating a medium based on the by-products of technological processes, which can act as nutritional sources and at the same time replace expensive laboratory preparations (e.g., peptone and yeast extract). The metabolic activity of P. freudenreichii was investigated in two different breeding environments: in a medium containing peptone, yeast extract, and biotin, and in a waste-based medium consisting of only apple pomace and potato wastewater. The highest production of propionic acid amounting to 14.54 g/L was obtained in the medium containing apple pomace and pure laboratory supplements with a yield of 0.44 g/g. Importantly, the acid production parameters in the waste medium reached almost the same level (12.71 g/L, 0.42 g/g) as the medium containing pure supplements. Acetic acid synthesis was more efficient in the waste medium; it was also characterized by a higher level of accumulated trehalose (59.8 mg/g d.s.). Thus, the obtained results show that P. freudenreichii bacteria exhibited relatively high metabolic activity in an environment with apple pomace used as a carbon source and potato wastewater used as a nitrogen source. This method of propioniate production could be cheaper and more sustainable than the chemical manner.

Anti-Inflammatory and Anti-Platelet Properties of Lipid Bioactives from Apple Cider By-Products.

The valorization of food industry by-products as sources of bioactive compounds is at the forefront of research in functional foods and nutraceuticals. This study focuses on bioactives of apple cider by-products (ACBPs) with putative cardio-protective properties. Total lipids (TLs) were extracted from ACBPs of apple varieties that are low (ACBP1), medium (ACBP2), and high (ACBP3) in tannins and were further separated into polar lipids (PLs) and neutral lipids (NLs). The functionality of these lipid extracts and of their HPLC-derived lipid fractions/PL subclasses were assessed in vitro against human platelet aggregation induced by the thrombotic and inflammatory platelet agonists platelet-activating factor (PAF) and adenosine diphosphate (ADP). The fatty acid profile of PLs and their most bioactive lipid fractions were evaluated by GC-MS analysis. The PL extracts exhibited higher specificity against the PAF-induced platelet aggregation compared to their anti-ADP effects, while TL and NL showed lower bioactivities in all ACBPs. HPLC analysis unveiled that the most bioactive PL from all ACBPs were those in PL fraction 3 containing phosphatidylcholines (PCs). PLs from all ACBPs and their PC bioactives were rich in polyunsaturated fatty acids (PUFAs) and especially in the essential omega-6 (n-6) linoleic acid (LA) and omega-3 (n-3) alpha linolenic acid (ALA), with favorably low values of the n-6/n-3 PUFA ratio, thus providing a rationale for their higher anti-inflammatory bioactivities. Within this study, highly bioactive PL compounds with strong anti-inflammatory and anti-platelet properties were identified in ACBPs, which can be potentially utilized for producing cardio-protective functional foods and/or nutraceuticals.