Fruit residues as substrates for single-cell oil production by Rhodococcus species: physiology and genomics of carbohydrate catabolism.

Strains belonging to R. opacus, R. jostii, R. fascians, R. erythropolis and R. equi exhibited differential ability to grow and produce lipids from fruit residues (grape marc and apple pomace), as well as single carbohydrates, such as glucose, gluconate, fructose and sucrose. The oleaginous species, R. opacus (strains PD630 and MR22) and R. jostii RHA1, produced higher yields of biomass (5.1-5.6 g L-1) and lipids (38-44% of CDW) from apple juice wastes, in comparison to R. erythropolis DSM43060, R. fascians F7 and R. equi ATCC6939 (4.1-4.3 g L-1 and less than 10% CDW of lipids). The production of cellular biomass and lipids were also higher in R. opacus and R. jostii (6.8-7.2 g L-1 and 33.9-36.5% of CDW of lipids) compared to R. erythropolis, R. fascians, and R. equi (3.0-3.6 g L-1 and less than 10% CDW of lipids), during cultivation of cells on wine grape waste. A genome-wide bioinformatic analysis of rhodococci indicated that oleaginous species possess a complete set of genes/proteins necessary for the efficient utilization of carbohydrates, whereas genomes from non-oleaginous rhodococcal strains lack relevant genes coding for transporters and/or enzymes for the uptake, catabolism and assimilation of carbohydrates, such as gntP, glcP, edd, eda, among others. Results of this study highlight the potential use of the oleaginous rhodococcal species to convert sugar-rich agro-industrial wastes, such as apple pomace and grape marc, into single-cell oils.

Fruit Wastes as a Valuable Source of Value-Added Compounds: A Collaborative Perspective.

The by-products/wastes from agro-food and in particular the fruit industry represents from one side an issue since they cannot be disposed as such for their impact on the environment but they need to be treated as a waste. However, on the other side, they are a source of bioactive healthy useful compounds which can be recovered and be the starting material for other products in the view of sustainability and a circular economy addressing the global goal of "zero waste" in the environment. An updated view of the state of art of the research on fruit wastes is here given under this perspective. The topic is defined as follows: (i) literature quantitative analysis of fruit waste/by-products, with particular regards to linkage with health; (ii) an updated view of conventional and innovative extraction procedures; (iii) high-value added compounds obtained from fruit waste and associated biological properties; (iv) fruit wastes presence and relevance in updated databases. Nowadays, the investigation of the main components and related bioactivities of fruit wastes is being continuously explored throughout integrated and multidisciplinary approaches towards the exploitation of emerging fields of application which may allow to create economic, environmental, and social value in the design of an eco-friendly approach of the fruit wastes.

Current trends of tropical fruit waste utilization.

Recent rapid growth of the world's population has increased food demands. This phenomenon poses a great challenge for food manufacturers in maximizing the existing food or plant resources. Nowadays, the recovery of health benefit bioactive compounds from fruit wastes is a research trend not only to help minimize the waste burden, but also to meet the intensive demand from the public for phenolic compounds which are believed to have protective effects against chronic diseases. This review is focused on polyphenolic compounds recovery from tropical fruit wastes and its current trend of utilization. The tropical fruit wastes include in discussion are durian (Durio zibethinus), mangosteen (Garcinia mangostana L.), rambutan (Nephelium lappaceum), mango (Mangifera indica L.), jackfruit (Artocarpus heterophyllus), papaya (Carica papaya), passion fruit (Passiflora edulis), dragon fruit (Hylocereus spp), and pineapple (Ananas comosus). Highlights of bioactive compounds in different parts of a tropical fruit are targeted primarily for food industries as pragmatic references to create novel innovative health enhancement food products. This information is intended to inspire further research ideas in areas that are still under-explored and for food processing manufacturers who would like to minimize wastes as the norm of present day industry (design) objective.

Optimization of Pectin Extraction from Melon Peel as a New Source of Pectin and Pectin Hydrolysate with Prebiotic Potential.

Food wastes have a large number of functional ingredients that have potential for valorization. Melon peels are increasingly produced as waste in food industries in Thailand. This study aimed to optimize pectin extraction conditions from melon peel for its prebiotic potential. Optimization was conducted using a response surface methodology and Box-Behnken experimental design. An analysis of variance indicated a significant interaction between the extraction conditions on extraction yield and degree of esterification (DE). These include pH and solvent-to-sample ratio. The conditions for the extraction of pectin with low DE (LDP), medium DE (MDP) and high DE (HDP) were optimized. Pectin hydrolysate from LDP, MDP and HDP was prepared by enzymatic hydrolysis into LPEH, MPEH and HPEH, respectively. LDP, MDP, HDP, LPEH, MPEH and HPEH were compared for their efficiency in terms of the growth of three probiotic strains, namely Lactobacillus plantarum TISTR 877, Lactobacillus casei TISTR 390 and Enterococcus faecium TISTR 1027. Among the samples tested, HPEH showed the highest ability as a carbon source to promote the growth and prebiotic activity score for these three probiotic strains. This study suggests that melon peel waste from agro-industry can be a novel source for prebiotic production.

Fruit waste: a current perspective for the sustainable production of pharmacological, nutraceutical, and bioactive resources.

Fruits are crucial components of a balanced diet and a good source of natural antioxidants, that have proven efficacy in various chronic illnesses. Various kinds of waste generated from fruit industries are considered a global concern. By utilizing this fruit waste, the international goal of "zero waste" can be achieved by sustainable utilization of these waste materials as a rich source of secondary metabolites. Moreover, to overcome this waste burden, research have focused on recovering the bioactive compounds from fruit industries and obtaining a new strategy to combat certain chronic diseases. The separation of high-value substances from fruit waste, including phytochemicals, dietary fibers, and polysaccharides which can then be used as functional ingredients for long-term health benefits. Several novel extraction technologies like ultrasound-assisted extraction (UAE), pressurized liquid extraction (PLE), and supercritical fluid extraction (SFE) could provide an alternative approach for successful extraction of the valuable bioactives from the fruit waste for their utilization as nutraceuticals, therapeutics, and value-added products. Most of these waste-derived secondary metabolites comprise polyphenols, which have been reported to have anti-inflammatory, insulin resistance-treating, cardiovascular disease-maintaining, probiotics-enhancing, or even anti-microbial and anti-viral capabilities. This review summarizes the current knowledge of fruit waste by-products in pharmacological, biological, and probiotic applications and highlights several methods for identifying efficacious bioactive compounds from fruit wastes.

Extraction of phenolic compounds from acerola by-products using chitosan solution, encapsulation and application in extending the shelf-life of guava.

Aiming the simplification of the production of chitosan nanoparticles as an encapsulating material, the primary approach of this study was to investigate the extraction of active compounds from acerola-pulp by-products directly in chitosan solution by using tip sonication. The results have shown that chitosan solution can be used as a good solvent, mainly for total phenolic compounds (TPC) extraction (1792.7 mg/100 g of dry by-product). The extract was submitted to ionic gelation process using, as counter-ion, the sodium tripolyphosphate to form loaded nanoparticles with TPC. The suspension was applied as protective coatings on the guavas. The nanoengineered coatings provided an effective barrier that delayed the maturation and maintained the green pigmentation for longer periods along with good firmness. To the best of our knowledge, this was the first study that uses chitosan solution as extraction solvent of TPC from food byproducts in order to facilitate the encapsulation process.

The avenue of fruit wastes to worth for synthesis of silver and gold nanoparticles and their antimicrobial application against foodborne pathogens: A review.

The emerging fruit wastes valorization tactic is a strategy for minimizing the dependence on toxic solvents and chemicals commonly used in the preparation of nanoparticles (NPs). Furthermore, the NPs have exhibited promising antimicrobial applications against foodborne pathogens. Hence, a timely review of this topic is in demand to provide a clear insight into the subject. In this article, the synthesis of silver and gold NPs from fruit wastes and their antimicrobial application against foodborne pathogens are reviewed. The extraction method, mechanism of NPs formation and influences of various experimental parameters on the shape and size of the NPs are described. In the second part of the article, antimicrobial activities against foodborne pathogens regarding the nature, optimum composition, surface structure, synergism and morphology of the NPs are reviewed. Furthermore, challenges and future trends related to the synthesis and antimicrobial application of fruit wastes-mediated NPs are discussed.

Bioactive metal oxide nanoparticles from some common fruit wastes and Euphorbia condylocarpa plant.

For the first time, the potential of orange and banana peels as fruit wastes was evaluated in contrast with Euphorbia condylocarpa as a widely distributed medicinal plant of Kurdistan, Iran, for biosynthesis of Fe3O4, CuO, ZnO, and TiO2 NPs. The extracts of the green sources were assessed to monitor the bioreducing phytochemicals inside them using the UV-Vis spectrophotometer. Moreover, the obtained green nanoparticles were identified using the micrograph and diffractogram techniques to show their size, shape, and morphology. Also, the antibacterial activities of the green NPs were investigated against common pathogenic bacteria of Pseudomonas aureus, Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae.

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.

Production of commercially important enzymes from Bacillus licheniformis KIBGE-IB3 using date fruit wastes as substrate.

BACKGROUND: Pakistan is one of the top five date fruit-producing countries and produced more than 30% wastes in picking, packing, storage, and commercialization stages. The date fruit wastes are usually considered inedible for humans and only used for livestock feed. In current research, Bacillus licheniformis KIBGE-IB3 was screened for pectinase, xylanase, cellulase, and amylase production using date fruit wastes as substrate through solid state fermentation. RESULTS: The B. licheniformis KIBGE-IB3 produced higher concentration of pectinase using date fruit wastes as substrate as compared to amylase, cellulase, and xylanase. B. licheniformis KIBGE-IB3 produced maximum pectinase using 5.0 g/dl date fruit wastes and 0.5 g/dl yeast extract. B. licheniformis KIBGE-IB3 required pH 7.0, 37 °C incubation temperature, and 72 h incubation period for maximum production of pectinase. CONCLUSION: It has been concluded that date fruit waste is a good source of biomass and can be utilized for the commercial production of pectinase.

Tailored nanocellulose structure depending on the origin. Example of apple parenchyma and carrot root celluloses.

Cellulose is the major polysaccharide of cell walls in every plant, making it one of the most abundant natural polymers on Earth. However, despite many decades of investigations, the supramolecular structure of cellulose and especially its variation in the cell walls of different plants have still not been fully revealed. In the present study, cellulose from the parenchymatic tissue of apple fruits and carrot roots was isolated, and nanocellulose was further prepared by high-intensity ultrasonication. AFM revealed that the obtained nanocellulose differed in dimension between the two plant species. Compared with carrot cellulose, whose nanocellulose was obtained in the form of whiskers, apple cellulose had longer and thinner nanofibrils. Both nanocellulose types also differed in terms of their crystalline structure. XRD data indicated that, compared with the apple cellulose, the carrot cellulose had a higher degree of crystallinity and larger crystallites. Moreover, FTIR and Raman spectroscopy revealed differences between the cellulose types in terms of their methine environment, hydroxymethyl conformations and skeletal vibrations. Additionally, with respect to their mechanical properties, the less crystalline apple cellulose and nanocellulose films were more elastic than the stiffer carrot cellulose and nanocellulose films. The possible reason for such differences between the two cellulose types is related to differences in plant tissue morphology and function. During development, apple fruit cell walls must withstand increasing turgor, probably higher that in the case of carrot tissue; therefore, the cellulose scaffolding must be elastic and strong. On the other hand, carrot, a root vegetable, also has to be strong enough to penetrate the soil as well as for its own growth; thus, the cell wall and cellulose scaffold have to be stiff and tough. Thus the structure of nanocellulose depends not only on the treatment but also on the cellulose source.