Processing of Apple Pomace for Bioactive Molecules

Concentrate Apple Juice Industry: Aroma and Pomace Valuation as Food Ingredients

Apple concentrate juice industry generates a flavored coproduct (apple aroma) recovered in the evaporation process, which is poorly valuated due to the lack of chemical characterization and standardization. In this study, industry apple aroma was characterized, allowing for the identification of 37 compounds, the majority esters (20), alcohols (7), and aldehydes (4). The storage temperature did not affect its volatile composition. Five key compounds were selected and monitored for 10 months of storage, and also compared with other three productions of another season allowing for observation of the same Aroma Index. Apple pomace was also used to produce a hydrodistillate. Contrary to the apple aroma, apple pomace hydrodistillate was unpleasant, reflected in a different volatile composition. Although no additional aroma fraction could be obtained from this wet byproduct, when dried, apple pomace presented 15 volatile compounds with toasted, caramel, sweet, and green notes. The infusions prepared with the dried apple pomace exhibited 25 volatile compounds with a very pleasant (fruity, apple-like, citrus, and spicy notes) and intense aroma. The addition of sugar changed the volatile profile, providing a less intense flavor, with almond, caramel, and sweet notes. These results show that apple aroma and pomace are high-quality flavoring agents with high potential of valuation as food ingredients.

Functionalization of Enzymatically Treated Apple Pomace from Juice Production by Extrusion Processing

Food by-products can be used as natural and sustainable food ingredients. However, a modification is needed to improve the technofunctional properties according to the specific needs of designated applications. A lab-scale twin-screw extruder was used to process enzymatically treated apple pomace from commercial fruit juice production. To vary the range of the thermomechanical treatment, various screw speeds (200, 600, 1000 min⁻¹), and screw configurations were applied to the raw material. Detailed chemical and functional analyses were performed to develop a comprehensive understanding of the impact of the extrusion processing on apple pomace composition and technofunctional properties as well as structures of individual polymers. Extrusion at moderate thermomechanical conditions increased the water absorption, swelling, and viscosity of the material. An increase in thermomechanical stress resulted in a higher water solubility index, but negatively affected the water absorption index, viscosity, and swelling. Scanning electron microscopy showed an extrusion-processing-related disruption of the cell wall. Dietary fiber analysis revealed an increase of soluble dietary fiber from 12.6 to 17.2 g/100 g dry matter at maximum thermo-mechanical treatment. Dietary fiber polysaccharide analysis demonstrated compositional changes, mainly in the insoluble dietary fiber fraction. In short, pectin polysaccharides seem to be susceptible to thermo-mechanical stress, especially arabinans as neutral side chains of rhamnogalacturonan I.

Varietal influence on phenolic constituents and nutritive characteristics of pomace obtained from apples grown in western Himalayas

Apple fruit processing is not variety specific in India, which affect the overall quality of the final processed product. The present study was aimed at elucidation of the nutritive value, phenolic content, antioxidant activity and bioactive phenolic constituents of five widely used apple varieties (Royal Delicious, Red Delicious, Golden Delicious, Red Chief and Red Gold) of western Himalayas. The pomace obtained from different varieties was evaluated to assess the fruit quality. Royal Delicious pomace had significantly high (p < 0.05) total dietary fibre content (42.63 ± 1.26%) together with soluble (8.25 ± 0.95%) and insoluble fibre (32.90 ± 0.89%), as compared to other apple varieties. The pomace samples were extracted with 70% aqueous methanol to obtain polyphenol enriched extracts. The results of Folin-Ciocalteau assay showed that hydroalcoholic extract of Royal Delicious pomace exhibit higher phenolic content as compared to other varieties and ranged between 2.19 ± 0.09 and 4.59 ± 0.47 mg GAE/g. Royal Delicious pomace also possess higher antioxidant capacity i.e. 3.35 ± 0.10 mg/g, 2.71 ± 0.10 mg/g and 4.67 ± 0.03 mg/g as measured by DPPH, ABTS free radical scavenging assay and FRAP reducing assay, respectively. The higher phenolic content in Royal Delicious pomace was also confirmed by RP-HPLC-DAD analysis. Results of HPLC analysis revealed the presence of phloridzin (487.07 ± 0.04 µg/g), quercetin (241.18 ± 0.03 µg/g), quercitrin (178.34 ± 0.02 µg/g) and quercetin-3-glucoside (195.21 ± 0.05 µg/g) as major constituents. Present results indicate that Royal Delicious variety is rich in dietary fibre and phenolic compounds that might be used by the food sector as a source of bioactive health promoting constituents/dietary supplements.

A simple procedure to obtain a medium-size oligogalacturonic acids fraction from orange peel and apple pomace wastes

Pectin oligosaccharides, which can be obtained from fruit wastes, have proven their potential as plant immune-system elicitors. Although the precise size of active species is still under investigation, medium size oligosaccharides have been reported as the most active. Three defined oligogalacturonic acid (OGAs) mixtures were produced from commercial pectin, orange peel and apple pomace residues. The methodology developed involves two sequential acid treatments followed by stepwise ethanol precipitation. Without the need of chromatographic separations, three different fractions were obtained. The fractions were analyzed by high performance anion exchange chromatography (HPAEC) and were completely characterized by mass spectrometry, showing that the small size, medium size and large size fractions contained OGAs of degree of polymerization 3 to 9, 6 to 18, and 16 to 55, respectively.

Development of red apple pomace extract/chitosan-based films reinforced by TiO2 nanoparticles as a multifunctional packaging material

A chitosan-based (CS) film was developed with nanosized TiO₂ and red apple pomace extract (APE). The intermolecular interactions of CS, TiO₂ and APE were evaluated by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction. TiO₂ nanoparticles remarkably improved the water vapor and UV-Vis light barrier properties, mechanical strength and thermal stability of CS-APE films. The strong antioxidant abilities of CS-APE and CS-TiO₂-APE films were characterized. Nano-TiO₂ and APE showed a synergistic enhancement of the antimicrobial activity in CS matrix. The addition of TiO₂ nano-particles into CS-APE films resulted the sensitive color variations, which applied successfully as an indicator to monitor the freshness of salmon fillets. Consequently, the development of CS-APE-TiO₂ film provides a new solution to convert rad apple pomace to an active and multifunctional food packaging material with considerable mechanical, antibacterial, antioxidant and pH-responsive color-changing properties.

Oral administration of potato peel extract affects serum blood metabolites, liver function and ameliorating oxidative stress induced in rabbits exposed to cold stress

This study investigated the effect of potato peel extract (PPE), orally administrated to rabbits, on serum blood metabolites and ameliorating oxidative stress induced by cold stress under Egyptian winter conditions. Twenty-four bucks grouped into three treatments (8 animals per group) were used for the experiment. The animals received 1.5 ml of water orally, containing 0 (PPE0), 25 (PPE25) or 50 (PPE50) mg PPE/kg live weight. Bucks were randomly assigned into three homogenous equal groups according to the level of PPE. Treatments were applied to each animal every two days over a period of three months including one month as an adaptation period. At the 8th week of the experiment, blood samples were collected from each buck and at the end of the experiment, bucks were slaughtered, and some organs were collected and weighed. The PPE improved (p < 0.05) blood total protein, albumin, globulin and glucose. The blood concentration of total lipid, cholesterol, triglyceride, low density lipoprotein and very low-density lipoprotein (were increased (p < 0.02) in PPE rabbits. Furthermore, PPE extract doses decreased (p < 0.001) oxidant thiobarbituric reactive substance (TBARS) in both blood and liver. Other liver and blood antioxidant system enzymes such as catalase, glutathione peroxidase, and superoxide dismutase were improved (p < 0.005) by PPE supplementation. Overall, oral administration of PPE up to 50 mg/kg live weight can have positive effects on rabbit health under cold stress.

The aspects of microbial biomass use in the utilization of selected waste from the agro-food industry

Cellular biomass of microorganisms can be effectively used in the treatment of waste from various branches of the agro-food industry. Urbanization processes and economic development, which have been intensifying in recent decades, lead to the degradation of the natural environment. In the first half of the 20th century, problems related to waste management were not as serious and challenging as they are today. The present situation forces the use of modern technologies and the creation of innovative solutions for environmental protection. Waste of industrial origin are difficult to recycle and require a high financial outlay, while the organic waste of animal and plant origins, such as potato wastewater, whey, lignin, and cellulose, is dominant. In this article, we describe the possibilities of using microorganisms for the utilization of various waste products. A solution to reduce the costs of waste disposal is the use of yeast biomass. Management of waste products using yeast biomass has made it possible to generate new metabolites, such as β-glucans, vitamins, carotenoids, and enzymes, which have a wide range of industrial applications. Exploration and discovery of new areas of applications of yeast, fungal, and bacteria cells can lead to an increase in their effective use in many fields of biotechnology.

Fate of Residual Pesticides in Fruit and Vegetable Waste (FVW) Processing

Plants need to be protected against pests and diseases, so as to assure an adequate production, and therefore to contribute to food security. However, some of the used pesticides are harmful compounds, and thus the right balance between the need to increase food production with the need to ensure the safety of people, food and the environment must be struck. In particular, when dealing with fruit and vegetable wastes, their content in agrochemicals should be monitored, especially in peel and skins, and eventually minimized before or during further processing to separate or concentrate bioactive compounds from it. The general objective of this review is to investigate initial levels of pesticide residues and their potential reduction through further processing for some of the most contaminated fruit and vegetable wastes. Focus will be placed on extraction and drying processes being amid the main processing steps used in the recuperation of bioactive compounds from fruit and vegetable wastes.

Valorisation of Fruits, their Juices and Residues into Valuable (Nano)materials for Applications in Chemical Catalysis and Environment

One of the most abundant wastes from all around the world is nutrient resources. Among them, fruits, their extracts, and residues comprise a major portion, which contain many valuable components that get lost during disposal or become burden on the shrinking landfills. These concerns are addressed by seeking sustainable processing methods that would have a minimal environmental impact. The crops contain renewable chemicals which are useful for catalysis, wastewater treatment, or preparation of nanomaterials; there has been an upsurge for the industrial applications of (nano)materials as their environmental and catalytic appliances is a fascinating subject to design cheaper and safer catalytic systems. Due to the excellent chemical properties of the fruit extracts, they have garnered attention as cost-effective catalysts and support materials. This review focuses on the preparation of (nano)materials and their catalytic and environmental applications and highlights the potential appliances and industrial benefits derived from these low-cost renewable and sustainable greener sources thus essentially converting waste into wealth.

Apple pomace as food fortification ingredient: A systematic review and meta-analysis

The present review aimed to investigate and analyze the use of byproduct apple pomace as a fortification ingredient in different types of foods. The data obtained from English published articles found on Web of Science, Scopus, and Google Scholar in the period from 2007 to 2019 were used for making the table overview and meta-analysis of results described in those studies. The systematic review confirmed the importance of apple pomace use in the food industry due to the beneficial nutritional profile and ecological issue (waste management). The main attributes of apple pomace are high content of antioxidant compounds and dietary fibers. Dietary fibers from apple pomace significantly increased total fiber content in enriched products-meaning that the transfer of the fortification can be declared health beneficial. The conducted meta-analysis showed unambiguously the different influence of apple pomace addition according to fortified food commodity. The fortification drawbacks were noticeable in plant food products because darker and brownish color was not evaluated positively by panelists. Oppositely, color, as one of the main sensory characteristics, was beneficially affected in animal origin food. The sensory properties, including color, play an important role in product acceptance by consumers. Besides color, animal origin products fortified by apple pomace showed the most acceptable textural properties and oxidative stability.

Apple pomace and rosemary extract ameliorates hepatic steatosis in fructose-fed rats: Association with enhancing fatty acid oxidation and suppressing inflammation

Apple pomace and rosemary (AR) have been reported to contain rich bioactive molecules, which have numerous metabolic effects. Our preliminary work revealed that AR ameliorated fructose-induced insulin resistance in rats by modulating sarcolemmal CD36 and glucose transporter-4. The present study aimed to further examine how AR improves metabolic disorders by investigating the effect of AR on hepatic steatosis induced by fructose overconsumption. The results demonstrated that AR (100 mg/kg daily by gavage for 5 weeks) attenuated chronic liquid fructose consumption-induced increases in liver triglyceride content in rats. Mechanistically, reverse transcription-quantitative PCR and western blot analysis results indicated that AR reversed fructose-induced suppression of hepatic peroxisome proliferator-activated receptor α, carnitine palmitoyl-transferase 1α, sirtuin 1 and peroxisome proliferator-activated receptor-γ coactivator 1α, which were associated with the fatty acid oxidative (FAO) pathway. In addition, AR treatment decreased the expression levels of the pro-inflammatory proteins NF-κB and tumor necrosis factor-α. However, AR had no effect on the genes related to lipogenesis and the very low-density lipoprotein-export pathway in rat liver. Thus, the present results suggested that AR treatment diminished long-term fructose overconsumption-induced fatty liver, which was associated with enhanced FAO and suppressed inflammation.

Penicillium oxalicum secretomic analysis identify plant cell wall degrading enzymes important for fruit juice extraction

Pectinases and other carbohydrate-active enzymes are important for the food industry, mainly for juice processing. In addition, the use of peels to produce enzymes can aggregate value to these agro-industrial residues and at the end of the process enhance qualitatively and quantitatively the juice production. In this work, three different extracts produced by Penicillium oxalicum LS09 using agro-industrial residues were optimized and analyzed by mass spectrometry. It was observed an increased production of pectinases in the medium containing orange peel and optimized for production of pectin lyase and pectinesterase (PE). Interestingly, not only pectinases, but also different plant cell wall degrading enzymes (i.e. glucanases, xylanases, arabinases), with a higher ratio (42/73) was identified in the medium optimized for PE. The crude extracts produced by P. oxalicum also reveal the potential for application in the fruit juice industry, showing an increased yield and qualitative characteristics of extracted juices. The presence of other cell wall-degrading enzymes identified by proteomics, reinforce the combination for obtaining clarified and depectinized juice in a single step.

Valorisation of pectin-rich agro-industrial residues by yeasts: potential and challenges

Pectin-rich agro-industrial residues are feedstocks with potential for sustainable biorefineries. They are generated in high amounts worldwide from the industrial processing of fruits and vegetables. The challenges posed to the industrial implementation of efficient bioprocesses are however manyfold and thoroughly discussed in this review paper, mainly at the biological level. The most important yeast cell factory platform for advanced biorefineries is currently Saccharomyces cerevisiae, but this yeast species cannot naturally catabolise the main sugars present in pectin-rich agro-industrial residues hydrolysates, in particular D-galacturonic acid and L-arabinose. However, there are non-Saccharomyces species (non-conventional yeasts) considered advantageous alternatives whenever they can express highly interesting metabolic pathways, natively assimilate a wider range of carbon sources or exhibit higher tolerance to relevant bioprocess-related stresses. For this reason, the interest in non-conventional yeasts for biomass-based biorefineries is gaining momentum. This review paper focuses on the valorisation of pectin-rich residues by exploring the potential of yeasts that exhibit vast metabolic versatility for the efficient use of the carbon substrates present in their hydrolysates and high robustness to cope with the multiple stresses encountered. The major challenges and the progresses made related with the isolation, selection, sugar catabolism, metabolic engineering and use of non-conventional yeasts and S. cerevisiae-derived strains for the bioconversion of pectin-rich residue hydrolysates are discussed. The reported examples of value-added products synthesised by different yeasts using pectin-rich residues are reviewed. Key Points • Review of the challenges and progresses made on the bioconversion of pectin-rich residues by yeasts. • Catabolic pathways for the main carbon sources present in pectin-rich residues hydrolysates. • Multiple stresses with potential to affect bioconversion productivity. • Yeast metabolic engineering to improve pectin-rich residues bioconversion. Graphical abstract.

Sustainable production of bio-based chemicals and polymers via integrated biomass refining and bioprocessing in a circular bioeconomy context

The sustainable production of bio-based chemicals and polymers is highly dependent on the development of viable biorefinery concepts using crude renewable resources for the production of diversified products. Within this concept, this critical review presents the availability of fractionated co-products and fermentable sugars that could be derived from major industrial and food supply chain side streams in EU countries. Fermentable sugars could be used for the production of bio-based chemicals and polymers. The implementation of biorefinery concepts in industry should depend on the evaluation of process efficiency and sustainability including techno-economic, environmental and social impact assessment following circular bioeconomy principles. Relevant sustainability indicators and End-of-Life scenarios have been presented. A case study on the techno-economic evaluation of bio-based succinic acid production from the organic fraction of municipal solid waste has been presented focusing on the evaluation of process profitability and feedstock requirements.

Apple Pomace as a Functional and Healthy Ingredient in Food Products: A Review

Apple pomace is a major by-product obtained during apple juice processing. Several million metric tons of apple pomace are estimated to be generated worldwide every year. However, the recovery rate of this by-product is low. Pomace is commonly disposed and thrown away as a waste, which results in environmental problems and even public health hazards. As a by-product of the apple juice processing industries, pomace contains plenty of different varieties of nutritionally important compounds, such as carbohydrates, phenolic compounds, dietary fiber and minerals. These important compounds can be recovered from apple pomace, or there is even a possibility of using apple pomace in the food systems directly or after minimal processing. Therefore, apple pomace can be utilized in food products to improve their health benefits and commercial values. This review focuses on the current food applications and influence of apple pomace on the characteristics of various food products.

Valorization of Fruits by-products to Unconventional Sources of Additives, Oil, Biomolecules and Innovative Functional Foods

Owning to the increase in the world population as well as the consumer's awareness on the health benefits of consumption of fruits, the demand for both fresh and processed fruits has been increased. The by-product and waste streams generated from fruit processing industries are extremely diverse, owning mainly to different fruits varieties and the wide range of the processes employed towards the production of the end fruit-based products. Due to the increasing production and processing of fruits, disposal of waste and by-product streams has become a serious issue, since these materials are prone to microbial spoilage. Also, the inappropriate waste management practices pose severe environmental issues. Furthermore, the costs of drying and storage of fruit processing residues are economically limiting factors hindering their further exploitation. Therefore, fruit processing by-products such as peels, seeds and unused flesh are often utilized as fertilizers. On the other hand, plant residues contain biomolecules such as vitamins, proteins, minerals, antioxidants and aromatic oil. Recovery of bioactive compounds holds a great potential for their usage in food industry as functional ingredients and nutraceuticals or in pharmaceutical and in cosmetic applications. So, valorization of plant fruit processing by-products to high-value added compounds, constitute a promising alternative not only for addressing fruit residues management issues but also leading to the production of functional food products of high nutritional value, with several potential beneficial health effects. The aim of this paper is to highlight current trends in addressing environmental issues caused by the production of high volumes of specific categories of fruit processing waste streams by investigating their potential usage as natural raw materials for the recovery of valuable bioactive compounds (such as polyphenols, dietary fibers or aromatic oil). The extracted nutrients may be used in the industrial food sector for the production of functional foods, nutraceuticals or even as health promoting natural pharmaceutical ingredients or additives for the production of innovative enriched foods. Highlights: • Fruit processing by product streams are rich in bioactive compounds. • Integration of fruit by-products and waste streams to value added products such as additives, unconventional oil, bioactive compounds and novel functional products is a very interesting approach regarding fruit processing residues exploitation. • Recovering of biomolecules from fruit residues by non-thermal processes could lead to the efficient production of highly purified functional ingredients. • Negative-valued fruit processing residues could be recycled for the production of health promoting value added products.

Effect of temperature and moisture contents on dielectric properties at 2.45 GHz of fruit and vegetable processing by-products

If processing alters the food-waste composition, dielectric properties are affected and need to be determined for efficient microwave processes.

Waste valorization: Identification of an ethanol tolerant bacterium Acetobacter pasteurianus SKYAA25 for acetic acid production from apple pomace

In present study, a potential bacterial isolate Acetobacter pasteurianus SKYAA25 was found to be very effective in the bioconversion of apple pomace to acetic acid. The isolated strain was tolerant to high ethanol concentrations of upto 14% and temperature of 42 °C. Fermentation of apple pomace alone in presence of brewing yeast produced 7.3% of bio-ethanol which was further used for acetic acid production. Apple pomace in combination with cane molasses produced 14% of bio-ethanol. The fermented bio-ethanol was used as medium for acetic acid production which yielded 52.4 g of acetic acid/100 g of DM (Dry Matter) of apple pomace. Hence, an ecofriendly process has been developed that is entirely based on microbial processing of apple pomace to produce acetic acid without involving commercial enzymes. The present bio-conversion will prove to be beneficial for utilizing food and beverage industrial waste in the production of acetic acid.

Lactic Acid Fermentation to Re-cycle Apple By-Products for Wheat Bread Fortification

Apple by-products (ABP) underwent fermentation (48 h at 30°C, Fermented-ABP) with a selected binary culture of Weissella cibaria PEP23F and Saccharomyces cerevisiae AN6Y19. Compared to Raw-ABP and Chemically Acidified-ABP (CA-ABP), fermentation markedly increased the hydration properties of ABP. Fermentation led to the highest increases of total and insoluble dietary fibers (DF). Raw-, CA- and Fermented-ABP, at 5 and 10% (w w^-1 of flour), were the ingredients for making fortified wheat breads. Addition of ABP and mainly fermentation enhanced dough water absorption and stability, and markedly increased the content of DF. Fortification mainly with 5% of Fermented-ABP did not interfere with bread rheology and color. As shown by profiling volatile compounds, Fermented-ABP imparted agreeable and specific sensory attributes, also appreciated by sensory analysis, and decreased bread hydrolysis index, and delayed mold contamination and firming. Fermented-ABP were suitable ingredients to fortify wheat bread formula, which agreed with bio-economy and environmental sustainability concepts.

Fruit Seeds as Sources of Bioactive Compounds: Sustainable Production of High Value-Added Ingredients from By-Products within Circular Economy

The circular economy is an umbrella concept that applies different mechanisms aiming to minimize waste generation, thus decoupling economic growth from natural resources. Each year, an estimated one-third of all food produced is wasted; this is equivalent to 1.3 billion tons of food, which is worth around US$1 trillion or even $2.6 trillion when social and economic costs are included. In the fruit and vegetable sector, 45% of the total produced amount is lost in the production (post-harvest, processing, and distribution) and consumption chains. Therefore, it is necessary to find new technological and environmentally friendly solutions to utilize fruit wastes as new raw materials to develop and scale up the production of high value-added products and ingredients. Considering that the production and consumption of fruits has increased in the last years and following the need to find the sustainable use of different fruit side streams, this work aimed to describe the chemical composition and bioactivity of different fruit seeds consumed worldwide. A comprehensive focus is given on the extraction techniques of water-soluble and lipophilic compounds and in vitro/in vivo functionalities, and the link between chemical composition and observed activity is holistically explained.

Bioactive potential of fruit and vegetable wastes

Fruits and vegetables are essential for human nutrition, delivering a substantial proportion of vitamins, minerals, and fibers in our daily diet. Unfortunately, half the fruits and vegetables produced worldwide end up as wastes, generating environmental issues caused mainly by microbial degradation. Most wastes are generated by industrial processing, the so-called by-products. These by-products still contain many bioactive compounds post-processing, such as macronutrients (proteins and carbohydrates) and phytochemicals (polyphenols and carotenoids). Recently, the recovery of these bioactive compounds from industry by-products has received significant attention, mainly due to their possible health benefits for humans. This chapter focuses on the bioactive potential of fruit and vegetable by-products with possible applications in the food industry (functional foods) and in the health sector (nutraceuticals).

Phytochemicals of Apple Pomace as Prospect Bio-Fungicide Agents against Mycotoxigenic Fungal Species-In Vitro Experiments

The phytochemical constituents of apple waste were established as potential antifungal agents against four crops pathogens, specifically, Botrytis sp., Fusarium oxysporum, Petriella setifera, and Neosartorya fischeri. Crude, purified extracts and fractions of apple pomace were tested in vitro to evaluate their antifungal and antioxidant properties. The phytochemical constituents of the tested materials were mainly represented by phloridzin and quercetin derivatives, as well as previously undescribed in apples, monoterpene-pinnatifidanoside D. Its structure was confirmed by 1D- and 2D-nuclear magnetic resonance (NMR) spectroscopic analyses. The fraction containing quercetin pentosides possessed the highest antioxidant activity, while the strongest antifungal activity was exerted by a fraction containing phloridzin. Sugar moieties differentiated the antifungal activity of quercetin glycosides. Quercetin hexosides possessed stronger antifungal activity than quercetin pentosides.

Co-preparation of pectin and cellulose from apple pomace by a sequential process

Apple pomace contains a plentiful pectin and cellulose resource which coexist with lignin and hemicellulose by a complex chemical and physical association in the plant cell walls. To increase the value and promote the utilization of apple pomace, it was used to produce pectin and cellulose by chemical treatments. In the case of 110 min, 10% (w/w) acetic acid and 100 °C, extraction yield of pectin reached 19.6%. Response surface methodology was applied to determine the main factors affecting the lignin removal rate (LR). LR was optimal at 70 °C, pH 4.0 and 6.0% NaClO₂ concentration for 2 h in a 20% (w/v) ratio. These conditions removed 89.8% lignin from depectinated apple pomace followed by sodium hydroxide treatment for the cellulose. Cellulose was achieved more than 80.7%. Consequently, a large-scale experimental analysis showed that 196.0 g of pectin and 243.9 g of cellulose (90.4% purity) was collectively prepared from 1000 g of apple pomace.

Exploitation of apple pomace towards extraction of triterpenic acids, antioxidant potential, cytotoxic effects, and inhibition of clinically important enzymes

Apple pomace (AP) utilised for analysis of triterpenic acids (TTAs) using HPLC-MS/MS. The methanol, ethanol and ethyl acetate extracts showed high phenolic content with significant antioxidant activity compared to chloroform and n-hexane. AP TTAs; ursolic acid, betulinic acid and maslinic acid showed potent antioxidant and enzyme inhibitory effects. The IC₅₀ values were 13.2-30.8 μg/mL (tyrosinase), 19.6-42.5 μg/mL (xanthine oxidase) and 16.6-38.6 μg/mL (urease) for AP extracts and 8.4-25.8 μg/mL (tyrosinase), 12.6-30.2 μg/mL (xanthine oxidase) and 10.1-28.6 μg/mL (urease) for TTAs, compared to the positive controls; kojic acid (10.4 ± 0.06 μg/mL), allopurinol (9.6 ± 0.04 μg/mL) and thiourea (8.9 ± 0.02 μg/mL) towards respective enzymes. UA showed a competitive type of inhibition for tyrosinase, while BA showed a noncompetitive type of inhibition towards xanthine oxidase. In addition, the AP extracts and TTAs exerted significant cytotoxic effects towards the proliferation of cancer cell lines. AP methanol extract (IC₅₀ of 38.5 ± 4.1, 47.1 ± 3.5, 70.6 ± 2.3, and 50.5 ± 3.9 μg/mL) and ursolic acid (IC₅₀ of 6.5 ± 0.7, 15.5 ± 1.4, 20.8 ± 1.3, and 5.6 ± 0.8 μg/mL) showed prominent anticancer activity on Hela, Skov-3, Caski, and NCL cancer cell lines, respectively. Thus, this study shows that the AP & TTAs could be utilized for functional food development and as a potent antioxidant, anticancer, skin whitening, and anti-urolithic agents.

Waste Utilization of Amla Pomace and Germinated Finger Millets for Value Addition of Biscuits

Fiber and vitamin C rich food plays an important role for human health. The aim of this study was to prepare the fiber and vitamin C rich biscuits and to quantify the levels of fiber, protein, fat, and vitamin C in prepared amla pomace biscuits. The fiber content of biscuits ranges from 1.7 – 5.2% and the maximum fiber was obtained for biscuits prepared from 15% amla pomace. The fat content of biscuits varies from 14.03 – 18.03% and the manimum fiber was obtained for biscuits prepared from 15% amla pomace. The prepared biscuits are rich in Vitamin C which increases with increase in pomace concentration and varies from 26.28 – 49.15 mg/ 100 gm. The ash content of biscuits ranges decreases with increased concentration of pomace and protein content varies from 7.27 – 7.52%.

Identification and Quantification of Bioactive Compounds in Diaphragma juglandis Fructus by UHPLC-Q-Orbitrap HRMS and UHPLC-MS/MS

Diaphragma juglandis fructus is the dry wooden diaphragm inside walnuts and a byproduct in food processing of walnut kernels. The purpose of our research is to enrich the information on compounds in Diaphragma juglandis fructus to further discover and exploit its potential nutritional value. In this study, new quali-quantitative analytical approaches were developed to identify and determine bioactive compounds in Diaphragma juglandis fructus. Two-hundred compounds, including hydrolyzable tannins, flavonoids, phenolic acids, and quinones, were identified by UHPLC-Q-Orbitrap HRMS, more than 150 of which were first discovered in Diaphragma juglandis fructus. Among them, 21 major dietary polyphenols with health-promoting effects were successfully quantified using UHPLC-MS/MS, with total contents of 2.88-6.18 mg/g. This successful characterization and quantification of bioactive compounds in Diaphragma juglandis fructus gives a better understanding of its potential nutritional value and supports efficiently developing and reusing it instead of discarding it as agrofood waste.

Development of Bio-Based Films and 3D Objects from Apple Pomace

Extensive quantities of apple pomace are generated annually but its disposal is still challenging. This study addresses this issue by introducing a new, environmentally-friendly approach for the production of sustainable biomaterials from apple pomace, containing 55.47% free sugars and a water insoluble fraction, containing 29.42 ± 0.44% hemicelluloses, 38.99 ± 0.42% cellulose, and 22.94 ± 0.12% lignin. Solution casting and compression molding were applied to form bio-based films and 3D objects (i.e., fiberboards), respectively. Using glycerol as plasticizer resulted in highly compact films with high tensile strength and low elongation (16.49 ± 2.54 MPa and 10.78 ± 3.19%, respectively). In contrast, naturally occurring sugars in the apple pomace showed stronger plasticizing effect in the films and resulted in a fluffier and connected structure with significantly higher elongation (37.39 ± 10.38% and 55.41 ± 5.38%, respectively). Benefiting from the self-binding capacity of polysaccharides, fiberboards were prepared by compression molding at 100 °C using glycerol or naturally occurring sugars, such as plasticizer. The obtained fiberboards exhibited tensile strength of 3.02⁻5.79 MPa and elongation of 0.93%⁻1.56%. Possible applications for apple pomace biomaterials are edible/disposable tableware or food packaging.

Extrusion of apple pomace increases antioxidant activity upon in vitro digestion

Apple pomace, a by-product of juice production, is a high-fibre, high-polyphenol functional food ingredient.

Apple Pomace Consumption Favorably Alters Hepatic Lipid Metabolism in Young Female Sprague-Dawley Rats Fed a Western Diet

Apple pomace, which is a waste byproduct of processing, is rich in several nutrients, particularly dietary fiber, indicating potential benefits for diseases that are attributed to poor diets, such as non-alcoholic fatty liver disease (NAFLD). NAFLD affects over 25% of United States population and is increasing in children. Increasing fruit consumption can influence NAFLD. The study objective was to replace calories in standard or Western diets with apple pomace to determine the effects on genes regulating hepatic lipid metabolism and on risk of NAFLD. Female Sprague-Dawley rats were randomly assigned (n = 8 rats/group) to isocaloric diets of AIN-93G and AIN-93G/10% w/w apple pomace (AIN/AP) or isocaloric diets of Western (45% fat, 33% sucrose) and Western/10% w/w apple pomace (Western/AP) diets for eight weeks. There were no significant effects on hepatic lipid metabolism in rats fed AIN/AP. Western/AP diet containing fiber-rich apple pomace attenuated fat vacuole infiltration, elevated monounsaturated fatty acid content, and triglyceride storage in the liver due to higher circulating bile and upregulated hepatic DGAT2 gene expression induced by feeding a Western diet. The study results showed the replacement of calories in Western diet with apple pomace attenuated NAFLD risk. Therefore, apple pomace has the potential to be developed into a sustainable functional food for human consumption.

A comprehensive analysis of the composition, health benefits, and safety of apple pomace

Apple processing results in peel, stem, seeds, and pulp being left as a waste product known as apple pomace. This review comprehensively assessed apple pomace composition for nutritional value and bioactive substances and evaluated potential health benefits and safety. Apple pomace is a rich source of health-benefitting nutrients, including minerals, dietary fiber, antioxidants, and ursolic acid, which suggests it has potential use as a dietary supplement, functional food, and/or food additive. Preclinical studies have found apple pomace and its isolated extracts improved lipid metabolism, antioxidant status, and gastrointestinal function and had a positive effect on metabolic disorders (eg, hyperglycemia, insulin resistance, etc.). Safety studies have shown apple pomace to be a safe livestock feed additive and to have pesticide concentrations within safety thresholds established for human consumption. Commercial development of apple pomace for human consumption requires more research focusing on standardized methods of nutrient reporting, mechanistic studies, and human clinical trials.

Diversity of bioactive compounds and antioxidant activity in Delicious group of apple in Western Himalaya

Apple contributes significantly to the livelihood and health of the people living in Himalayan regions. Among others, the Delicious group of apple is known for their health promoting and income generating attributes. However, the systematic investigation on morphological and phytochemical attributes of the apple growing in Indian Himalayan region is poorly known. An altitude-dependent variation in the fruit quality traits and phytochemical diversity was observed. The Royal Delicious was found rich in total tannin, flavonoids, flavonols, antioxidant activity [2,2-azinobis (3-ethylbenzothiazoline-6-sulphonic acid), 2,2-Diphenyl-1-picryhydrazyl, Ferric reducing antioxidant power], procyanidin B₂, phloridzin and gallic acid; Red Delicious for total phenol and epicatechin and Golden Delicious for chlorogenic acid. The cultivar and altitude-dependent variation of phenolic profile in peel and pulp portion emphasizes genotype-specific biosynthesis of phenolic compounds in regulatory mechanisms. It is suggested that selection of suitable altitude and cultivars is required for harnessing the maximum phytochemical and antioxidant activity for benefits to human consumption.

Using an artificial neural network to predict the optimal conditions for enzymatic hydrolysis of apple pomace

The enzymatic degradation of lignocellulosic biomass such as apple pomace is a complex process influenced by a number of hydrolysis conditions. Predicting optimal conditions, including enzyme and substrate concentration, temperature and pH can improve conversion efficiency. In this study, the production of sugar monomers from apple pomace using commercial enzyme preparations, Celluclast 1.5L, Viscozyme L and Novozyme 188 was investigated. A limited number of experiments were carried out and then analysed using an artificial neural network (ANN) to model the enzymatic hydrolysis process. The ANN was used to simulate the enzymatic hydrolysis process for a range of input variables and the optimal conditions were successfully selected as was indicated by the R ² value of 0.99 and a small MSE value. The inputs for the ANN were substrate loading, enzyme loading, temperature, initial pH and a combination of these parameters, while release profiles of glucose and reducing sugars were the outputs. Enzyme loadings of 0.5 and 0.2 mg/g substrate and a substrate loading of 30% were optimal for glucose and reducing sugar release from apple pomace, respectively, resulting in concentrations of 6.5 g/L glucose and 28.9 g/L reducing sugars. Apple pomace hydrolysis can be successfully carried out based on the predicted optimal conditions from the ANN.

Methyl acrylate modified apple pomace as promising adsorbent for the removal of divalent metal ion from industrial wastewater

Polymerized apple pomace (PoAP) surface was evaluated as adsorbent for the removal of Pb⁺², Cd⁺², and Ni⁺² ions from aqueous solution. PoAP was characterized by FTIR, SEM, EDS, XRD, and BET surface area analyzer. Furthermore, the adsorption influencing parameters such as dose, pH, time, concentration, and temperature were optimized for maximum removal of metal ions from aqueous solution. The maximum monolayer adsorption capacity of PoAP was found to be 106, 34.12, and 19.45 mg g^-1, for Pb⁺², Cd⁺², and Ni⁺² ions respectively, using the Langmuir isotherm model. The rate of adsorption was evaluated using pseudo-second order kinetics and intra-particle diffusion. The adsorption data followed pseudo-second order kinetic with the correlation coefficient (r ²) from 0.99-1 at all concentration. Thermodynamic study revealed endothermic nature of Pb⁺² and Cd⁺² adsorption and exothermic for Ni⁺² ions. The rate of adsorption for binary and tertiary mixtures of Pb⁺², Ni⁺², and Cd⁺² metal ion was studied using the ideal adsorbed solution theory. The regeneration study revealed that PoAP could be re-utilized up to 4 cycles for Pb⁺² and 2 cycles for Cd⁺² and Ni⁺² ions. PoAP was successfully applied to real industrial wastewater for the removal of Pb⁺², Cd⁺², and Ni⁺² ions.

Ursolic acid from apple pomace and traditional plants: A valuable triterpenoid with functional properties

Apple juice production generates a large amount of residue comprising mainly peels, seeds, and pulp, known as apple pomace. In the global context, Brazil ranks 11th in apple production and thousands of tons of apple pomace are produced every year. This by-product is little explored, since it is a rich and heterogeneous mixture, containing interesting phytochemical groups. Among them, ursolic acid (UA) has attracted attention because of its therapeutic potential. UA is a pentacyclic triterpene found too in several traditional plants, and has shown several functional properties such as antibacterial, antiprotozoal, anti-inflammatory and antitumor. Therefore, this review attempts to shed some light on the economical viability of apple and apple pomace as sources of bioactive compounds, highlighting the UA extraction, and its main functional properties published in the last 5years (2010-2015).

Plant Food Residues as a Source of Nutraceuticals and Functional Foods

This chapter describes the use of different plant and vegetable food residues as nutraceuticals and functional foods. Different nutraceuticals are mentioned and explained. Their uses are well addressed along with their disease management and their action as nutraceutical delivery vehicles.

Microbial Enzyme Production Using Lignocellulosic Food Industry Wastes as Feedstock: A Review

Enzymes are of great importance in the industry due to their substrate and product specificity, moderate reaction conditions, minimal by-product formation and high yield. They are important ingredients in several products and production processes. Up to 30% of the total production cost of enzymes is attributed to the raw materials costs. The food industry expels copious amounts of processing waste annually, which is mostly lignocellulosic in nature. Upon proper treatment, lignocellulose can replace conventional carbon sources in media preparations for industrial microbial processes, such as enzyme production. However, wild strains of microorganisms that produce industrially important enzymes show low yield and cannot thrive on artificial substrates. The application of recombinant DNA technology and metabolic engineering has enabled researchers to develop superior strains that can not only withstand harsh environmental conditions within a bioreactor but also ensure timely delivery of optimal results. This article gives an overview of the current complications encountered in enzyme production and how accumulating food processing waste can emerge as an environment-friendly and economically feasible solution for a choice of raw material. It also substantiates the latest techniques that have emerged in enzyme purification and recovery over the past four years.