Fruit Characteristics, Peel Nutritional Compositions, and Their Relationships with Mango Peel Pectin Quality

Production of biodegradable food packaging from mango peel via enzymatic hydrolysis and polyhydroxyalkanoates synthesis: A review on microbial intervention

The rising environmental problem of plastic packaging waste has led to the development of sustainable alternatives, particularly for food packaging. Polyhydroxyalkanoates (PHAs) are biodegradable, thermoplastic polyesters. They are employed in the production of various products, including packaging films. The bio-based nature and appropriate features of PHAs, similar to conventional synthetic plastics, have garnered significant attention from researchers and industries. The current study aimed to produce biodegradable food packaging using mango peel (a major agricultural waste) with enzymatic hydrolysis and PHAs synthesis. Mango peel is the hub for macro-and micronutrients, including phytochemicals. The process includes an enzymatic hydrolysis step that converts complex carbohydrates into simple sugars using mango peel as a substrate. The produced sugars are used as raw materials for bacteria to synthesize PHAs, which are a class of biodegradable polymers produced by these microorganisms that can serve as packaging materials in the food industry. To solve environmental problems and increase the utilization of agricultural by-products, this review presents a practical method for producing food packaging that is environmentally friendly.

Simple one-step treatment for saccharification of mango peels using an optimized enzyme cocktail of Aspergillus niger ATCC 9642

Developing efficient microbiological methods to convert polysaccharide-rich materials into fermentable sugars, particularly monosaccharides, is vital for advancing the bioeconomy and producing renewable chemicals and energy sources. This study focused on optimizing the production conditions of an enzyme cocktail from Aspergillus niger ATCC 9642 using solid-state fermentation (SSF) and assessing its effectiveness in saccharifying mango peels through a simple, rapid, and efficient one-step process. A rotatable central composite design was employed to determine optimal conditions of moisture, time, and pH for enzyme production in SSF medium. The optimized enzyme cocktail exhibited cellulase activity (CMCase) at 6.28 U/g, filter paper activity (FPase) at 3.29 U/g, and pectinase activity at 117.02 U/g. These optimal activities were achieved with an SSF duration of 81 h, pH of 4.66, and a moisture content of 59%. The optimized enzyme cocktail effectively saccharified the mango peels without the need for chemical agents. The maximum saccharification yield reached approximately 81%, indicating efficient conversion of mango peels into sugars. The enzyme cocktail displayed consistent thermal stability within the tested temperature range of 30-60°C. Notably, the highest sugar release occurred within 36 h, with glucose, arabinose, galactose, and xylose being the primary monosaccharides released during saccharification. This study highlights the potential application of Aspergillus niger ATCC 9642 and SSF for enzymatic production, offering a simple and high-performance process for monosaccharide production. The optimized enzyme cocktail obtained through solid-state fermentation demonstrated efficient saccharification of mango peels, suggesting its suitability for industrial-scale applications.

Utilization of the sugar fraction from Arabica coffee pulp as a carbon source for bacteria producing cellulose and cytotoxicity with human keratinocyte

Coffee pulp (CP), a by-product of coffee production, is an underutilized resource with significant potential value. CP contains monosaccharides that can serve as an ideal carbon source for bacterial cultivation, enabling the production of value-added components such as medical-grade cellulose. Herein, we extracted the sugar fraction from Arabica CP and used it as a supplement in a growing media of a bacteria cellulose (BC), Komagataeibacter nataicola. The BC was then characterized and tested for cytotoxicity. The CP sugar fraction yielded approximately 7% (w/w) and contained glucose at 4.52 mg/g extract and fructose at 7.34 mg/g extract. Supplementing the sugar fraction at different concentrations (0.1, 0.3, 0.5, 0.7, and 1 g/10 mL) in sterilized glucose yeast extract broth, the highest yield of cellulose (0.0020 g) occurred at 0.3 g/10 mL. It possessed similar physicochemical attributes to the BC using glucose, with some notable improvements in fine structure and arrangement of the functional groups. In cytotoxicity assessments on HaCaT keratinocyte cells, bacterial cellulose concentrations of 2-1000 µg/mL exhibited viability of ≥ 80%. However, higher concentrations were toxic. This research innovatively uses coffee pulp for bacterial cellulose, aligning with the principles of a bio-circular economy that focuses on sustainable biomass utilization.

Mango Peels as an Industrial By-Product: A Sustainable Source of Compounds with Antioxidant, Enzymatic, and Antimicrobial Activity

Plant waste materials are important sources of bioactive compounds with remarkable health-promoting benefits. In particular, industrial by-products such as mango peels are sustainable sources of bioactive substances, with antioxidant, enzymatic, and antimicrobial activity. Appropriate processing is essential to obtain highly bioactive compounds for further use in generating value-added products for the food industry. The objective of the study was to investigate and compare the biological activity of compounds from fresh and dried mango peels obtained by different conventional methods and unconventional extraction methods using supercritical fluids (SFE). The highest total phenolic content (25.0 mg GAE/g DW) and the total content of eight phenolic compounds (829.92 µg/g DW) determined by LC-MS/MS were detected in dried mango peel extract obtained by the Soxhlet process (SE). SFE gave the highest content of proanthocyanidins (0.4 mg PAC/g DW). The ethanolic ultrasonic process (UAE) provided the highest antioxidant activity of the product (82.4%) using DPPH radical scavenging activity and total protein content (2.95 mg protein/g DW). Overall, the dried mango peels were richer in bioactive compounds (caffeic acid, chlorogenic acid, gallic acid, catechin, and hesperidin/neohesperidin), indicating successful preservation during air drying. Furthermore, outstanding polyphenol oxidase, superoxide dismutase (SOD), and lipase activities were detected in mango peel extracts. This is the first study in which remarkable antibacterial activities against the growth of Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus) were evaluated by determining the microbial growth inhibition rate after 12 and 24 h incubation periods for mango peel extracts obtained by different methods. Ethanolic SE and UAE extracts from dried mango peels resulted in the lowest minimum inhibitory concentrations (MIC90) for all bacterial species tested. Mango peels are remarkable waste products that could contribute to the sustainable development of exceptional products with high-added value for various applications, especially as dietary supplements.

Towards Valorization of Food-Waste-Derived Pectin: Recent Advances on Their Characterization and Application

Pectin, a natural biopolymer, can be extracted from food waste biomass, adding value to raw materials. Currently, commercial pectin is mostly extracted from citrus peels (85.5%) and apple pomace (14.0%), with a small segment from sugar beet pulp (0.5%). However, driven by high market demand (expected to reach 2.12 billion by 2030), alternative agro-industrial waste is gaining attention as potential pectin sources. This review summarizes the recent advances in characterizing pectin from both conventional and emerging food waste sources. The focus is the chemical properties that affect their applications, such as the degree of esterification, the neutral sugars' composition, the molecular weight, the galacturonic acid content, and technological-functional properties. The review also highlights recent updates in nutraceutical and food applications, considering the potential use of pectin as an encapsulating agent for intestinal targeting, a sustainable biopolymer for food packaging, and a functional and emulsifying agent in low-calorie products. It is clear from the considered literature that further studies are needed concerning the complexity of the pectin structure extracted from emerging food waste raw materials, in order to elucidate their most suitable commercial application.

Preparation and Characterization of a Novel Artemisia Oil Packaging Film and Its Application in Mango Preservation

In this work, a new food packaging film was synthesized via blending Artemisia oil (AO) into soybean protein isolate (SPI) and gelatin (Gel) for the postharvest storage of mango. The morphological architecture and mechanical properties of the films were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), and other technologies. The results show that the prepared films had relatively flat surfaces with good mechanical properties. AO enhanced the light-blocking ability of the film, increased the hydrophobicity, and affected the moisture content and water solubility of the film to a certain extent. Furthermore, the antioxidant performance and antifungal (Colletotrichum gloeosporioides) capacity of the films increased with higher AO concentration due to the presence of the active components contained in AO. During mango storage applications, the films showed good freshness retention properties. The above results indicate that SPI-Gel films containing AO have excellent physicochemical and application properties and have great potential in the field of food packaging.

Production of Single-Cell Protein from Fruit Peel Wastes Using Palmyrah Toddy Yeast

Single-cell protein (SCP) from agro-waste material has gained increased attention in the recent past as a relatively cheap and alternative protein source to meet the nutritional demand generated by the fast-growing population. Furthermore, bioconversion of these wastes into SCP such as value-added products reduce the environmental-related issues. In this study, locally available pineapple (Ananas comosus), watermelon (Citrullus lanatus), papaya (Carica papaya), sour orange (Citrus medica), banana (Musa acuminata) and mango (Mangifera indica) peel wastes were investigated for their suitability to produce SCP using palmyrah (Borassus flabellifer) toddy carrying natural mixed yeast and bacteria culture under liquid state fermentation system. Moreover, this study attempted to select the best substrate and the optimized process condition for SCP production to increase the protein yield. The physicochemical properties of selected fruit peels were analyzed. The sterilized peel extracts (10%, v/v) were inoculated with 5 mL of palmyrah toddy and allowed to ferment in a shaking incubator at 100 rpm for 48 h in triplicate At the end of fermentation, the sediments were collected by centrifugation at 1252× g, oven-dried, and the dry weight was taken to determine the protein content. The biomass yield ranged from 5.3 ± 0.6 to 11.7 ± 0.8 g/L, with the least biomass yield being observed with watermelon peels while the maximum yield was observed with papaya peels. Papaya peel generated a significantly higher (p < 0.05) amount of protein (52.4 ± 0.4%) followed by pineapple (49.7 ± 1.3%), watermelon (45.2 ± 0.7%), banana (30.4 ± 0.6%), sour orange (29.5 ± 1.2%) and mango (24.6 ± 0.2%) peels. The optimum condition for the fermentation of papaya waste was pH 5.0, 25 °C, and 24 h. Nucleic acid reduction treatment significantly reduces dry weight and protein content of biomass. It can be concluded that papaya peel waste is a suitable substrate for protein-rich cell biomass production using the natural toddy mixed culture of palmyrah.

A Comparative Metabolomics Approach for Egyptian Mango Fruits Classification Based on UV and UPLC/MS and in Relation to Its Antioxidant Effect

Mango (Mangifera indica L.) is a tropical climacteric fruit that encompasses a myriad of metabolites mediating for its nutritive value, unique taste, flavor, and medicinal uses. Egypt is among the top mango producers worldwide, albeit little characterization has been made toward its fruits’ chemical composition. This study aims to assess metabolites difference via comparative profiling and fingerprinting of Egyptian mango in context to its cultivar (cv.) type and/or growth province. To achieve such goal, hyphenated chromatographic techniques (UPLC/MS) and UV spectroscopy were employed and coupled to multivariate data analysis for Egyptian mango fruits’ classification for the first time. UPLC/MS led to the detection of a total of 47 peaks identified based on their elution times and MS data, belonging to tannins as gallic acid esters, flavonoids, xanthones, phenolic acids and oxylipids. UV/Vis spectra of mango fruits showed similar absorption patterns mostly attributed to the phenolic metabolites, i.e., gallic acid derivatives and phenolic acids showing λmax at ca. 240 and 270 nm. Modeling of both UPLC/MS and UV data sets revealed that cv. effect predominated over geographical origin in fruits segregation. Awees (AS) cv. showed the richest phenolic content and in agreement for its recognition as a premium cv. of mango in Egypt. Results of total phenolic content (TPC) assay revealed that AS was the richest in TPC at 179.1 mg GAE/g extract, while Langara from Ismailia (LI) showed the strongest antioxidant effect at 0.41 mg TE/g extract. Partial least square modeling of UV fingerprint with antioxidant action annotated gallates as potential contributor to antioxidant effect though without identification of exact moieties based on UPLC/MS. The study is considered the first-time investigation of Egyptian mango to aid unravel phytoconstituents responsible for fruits benefits using a metabolomics approach.

Gene expression analysis during the fruit development in dehiscent and indehiscent Bixa orellana L. accessions

Fruit morphology and dehiscence-related genes were analyzed in dehiscent N4P and dehiscent P12 Bixa orellana accessions. Fruit architecture (exocarp and pericarp cells, trichomes, vascular bundles, vesicles, and bixin cells) documented by Scanning electron microscopy (SEM) morphology, blue toluidine stain, and phloroglucinol and hydrochloric acid (PHCL) stain was similar in both accessions. Although, the dehiscent zone (DZ) was higher in the indehiscent P12 B. orellana accession, lignification values, obtained by phloroglucinol and hydrochloric acid stain, within the DZ remain was similar in both variants being lower at 34 days after floral anthesis in the dehiscent N4P B. orellana accession. Dehiscence-related genes APETALA (AP2), SHATTERPROOF (SHP), and SPATULA (SPT) were identified on the reported B. orellana transcriptome (SRX1117606). Real-time quantitative polymerase chain reaction primers build by using these genes allow observing a differential expression during six fruit development stages. In both B. orellana accessions, the AP2 transcripts have a reduced expression, whereas the SHP transcripts were significantly higher during the first two days and ten days of development. SPT transcripts show an expression differential between both accessions being significantly higher in the dehiscent N4P, peaking with 9.66% at 42 days after floral anthesis (DAFA) of development. SPT transcription profile suggested that this gene has an important role during the fruit opening in the dehiscent N4P B. orellana accession.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12298-022-01180-w.

Mango Pectic Oligosaccharides: A Novel Prebiotic for Functional Food

Prebiotics are functional food ingredients that assist probiotic growth and render many other health benefits. Mango peel is the biomass of the processing industry and has recently been value-added as a dietary fiber pectin. Besides its general use as a food additive, mango peel pectin (MPP) is partially hydrolyzed by pectinase to obtain pectic oligosaccharides (POSs) that have recently gained attention as novel prebiotic products and in medical research. This review describes probiotic candidates responsible for the digestion of pectin derivatives and the advantages of POSs as functional additives and their current best retrieval options. Mango pectic oligosaccharide (MPOS) recovery from low methoxyl MPP from mango with prebiotic performance both in vivo and in vitro environments is discussed. Current research gaps and potential developments in the field are also explored. The overall worthiness of this article is the potential use of the cheap-green food processing bioresource for high-value components.

Mango Peel Pectin: Recovery, Functionality and Sustainable Uses

Concerns regarding the overconsumption of natural resources has provoked the recovery of biopolymers from food processing biomass. Furthermore, the current market opportunity for pectin in other areas has increased, necessitating the search for alternative pectin resources. This is also a step towards the sustainable and circular green economy. Mango peel is the byproduct of agro-processing and has been used for high value-added components such as polysaccharide biopolymers. Pectin derived from the peel is yet to be exploited to its greatest extent, particularly in terms of its separation and physiochemical properties, which limit its applicability to dietary fiber in culinary applications. The functionality of the mango peel pectin (MPP) strongly depends on the molecular size and degree of esterification which highlight the importance of isolation and characterisation of pectin from this novel resource. This article therefore provides a useful overview of mango peel as a potential biomaterial for the recovery of MPP. Different extraction techniques and the integrated recovery were also discussed. The utilisation of MPP in different industrial schemes are also detailed out from different perspectives such as the pharmaceutical and biotechnology industries. This review convincingly expresses the significance of MPP, providing a sustainable opportunity for food and pharmaceutical development.

Recovery of Polyphenolic Fraction from Arabica Coffee Pulp and Its Antifungal Applications

Coffee pulp is one of the most underutilised by-products from coffee processing. For coffee growers, disposing of this agro-industrial biomass has become one of the most difficult challenges. This study utilised this potential biomass as raw material for polyphenolic antifungal agents. First, the proportion of biomass was obtained from the Arabica green bean processing. The yield of by-products was recorded, and the high-potency biomass was serially extracted with organic solvents for the polyphenol fraction. Quantification of the polyphenols was performed by High Performance Liquid Chromatography (HPLC), then further confirmed by mass spectrometry modes of the liquid chromatography–quadrupole time-of-flight (QTOF). Then, the fraction was used to test antifungal activities against Alternaria brassicicola, Pestalotiopsis sp. and Paramyrothecium breviseta. The results illustrated that caffeic acid and epigallocatechin gallate represented in the polyphenol fraction actively inhibited these fungi with an inhibitory concentration (IC50) of 0.09, 0.31 and 0.14, respectively. This study is also the first report on the alternative use of natural biocontrol agent of P. breviseta, the pathogen causing leaf spot in the Arabica coffee.