Applications of plant-derived food by-products to maintain quality of postharvest fruits and vegetables

Advances in valorization of sweet potato peels: A comprehensive review on the nutritional compositions, phytochemical profiles, nutraceutical properties, and potential industrial applications

During food production, food processing, and supply chain, large amounts of food byproducts are generated and thrown away as waste, which to a great extent brings about adverse consequences on the environment and economic development. The sweet potato (Ipomoea batatas L.) is cultivated and consumed in many countries. Sweet potato peels (SPPs) are the main byproducts generated by the tuber processing. These residues contain abundant nutrition elements, bioactive compounds, and other high value-added substances; therefore, the reutilization of SPP holds significance in improving their overall added value. SPPs contain abundant phenolic compounds and carotenoids, which might contribute significantly to their nutraceutical properties, including antioxidant, antimicrobial, anticancer, prebiotic, anti-inflammatory, wound-healing, and lipid-lowering effects. It has been demonstrated that SPP could be promisingly revalorized into food industry, including: (1) applications in diverse food products; (2) applications in food packaging; and (3) applications in the recovery of pectin and cellulose nanocrystals. Furthermore, SPP could be used as promising feedstocks for the bioconversion of diverse value-added bioproducts through biological processing.

Unravelling the effect of extraction on anthocyanin functionality and prebiotic potential

Anthocyanins, considered as prebiotic ingredients for functional foods, were extracted from black soybean (BS), black grape (BG), black carrot (BCPm), and black rice (BR) using conventional solvent extraction (CSE) and microwave-assisted extraction (MAE). The study employed a split-plot design with CSE and MAE as main plot factors and anthocyanin extracts (AEs) as subplot factors. Anthocyanins were evaluated for stability (polymeric color, degradation index) and functionality (antioxidant capacity). Prebiotic potential on Lactobacillus rhamnosus, Lactobacillus acidophilus, Weissella confusa was assessed in fermented soymilk. MAE showed higher extraction yield than CSE in BG (3-fold), BS (2-fold), BCPm (1.2-fold), and BR (1.6-fold). Black grape (1255.76 mg/L) and black soybean (976.5 mg/L) had highest anthocyanin with better stability, functionality, and prebiotic potential. The SCFA concentration (propionic acid and butyric acid) increased significantly in BG fortified-fermented soymilk. Overall, anthocyanin-enriched soymilk exhibited higher prebiotic potential, with MAE as the superior extraction method for anthocyanin functionality and stability.

Composite Coating of Oleaster Gum Containing Cuminal Keeps Postharvest Quality of Cherry Tomatoes by Reducing Respiration and Potentiating Antioxidant System

Exploring the green and affordable protection of perishable cherry tomato fruits during storage, herein, the protective efficacy, and its underpinning mechanisms, of a coating of oleaster gum, alone or incorporated with cuminal, on cherry tomatoes stored at ambient temperature was investigated. The composite coating of oleaster gum with 0.1% cuminal reduced the decay, respiration rate, weight loss, and softening of the fruits and decelerated the decreases in their total soluble solid, titratable acidity, and soluble protein levels, and therefore maintained their marketability. Furthermore, it reduced the accumulation of O2·- and H2O2 in the fruits and mitigated cell membrane lipid oxidation and permeabilization, thereby retarding their senescence. Instrumentally, it elevated the activities of superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase and the levels of ascorbic acid and glutathione. This potentiation of the fruits' antioxidant system makes this composite coating a promising approach to keeping the postharvest quality of perishable fruits.

Moisture loss inhibition with biopolymer films for preservation of fruits and vegetables: A review

In cold storage, fruits and vegetables still keep a low respiratory rate. Although cold storage is beneficial to maintain the quality of some fruits and vegetables, several factors (temperature and humidity fluctuations, heat inflow, air velocity, light, etc.) will accelerate moisture loss. Biopolymer films have attracted great attention for fruits and vegetables preservation because of their biodegradable and barrier properties. However, there is still a certain amount of water transfer occurring between storage environment/biopolymer films/fruits and vegetables (EFF). The effect of biopolymer films to inhibit moisture loss of fruits and vegetables and the water transfer mechanism in EFF system need to be studied systematically. Therefore, the moisture loss of fruits and vegetables, crucial properties, major components, fabrication methods, and formation mechanisms of biopolymer films were reviewed. Further, this study highlights the EFF system, responses of fruits and vegetables, and water transfer in EFF. This work aims to clarify the characteristics of EFF members, their influence on each other, and water transfer, which is conducive to improving the preservation efficiency of fruits and vegetables purposefully in future studies. In addition, the prospects of studies in EFF systems are shown.

Multiomics analyses of the effects of LED white light on the ripening of apricot fruits

INTRODUCTION

Apricot (Prunus armeniaca L.) fruits are highly perishable and prone to quality deterioration during storage and transportation.

OBJECTIVES

To investigate the effects of LED white light treatment on postharvest ripening of fruits using metabolomics, transcriptomics, and ATAC-Seq analysis.

METHODS

Fruits were exposed to 5 μmol m-2 s-1 LED white light for 12 h followed by 12 h of darkness at 20 °C daily for 12 days. The effects of the treatments on the physiological and nutritional quality of the fruits were evaluated. These data were combined with transcriptomic, metabolomic, and ATAC-Seq data from fruits taken on 8 d of treatment to provide insight into the potential mechanism by which LED treatment delays ripening.

RESULTS

LED treatment activated pathways involved in ascorbate and aldarate metabolism and flavonoid and phenylpropanoid biosynthesis. Specifically, LED treatment increased the expression of UDP-sugar pyrophosphorylase (USP), L-ascorbate peroxidase (AO), dihydroflavonol 4-reductase (DFR), chalcone synthase (CHS), and caffeoyl-CoA O-methyltransferase (CCOAOMT1), leading to the accumulation of caffeoyl quinic acid, epigallocatechin, and dihydroquercetin and the activation of anthocyanin biosynthesis. LED treatment also affected the expression of genes associated with plant hormone signal transduction, fruit texture and color transformation, and antioxidant activity. The notable genes affected by LED treatment included 1-aminocyclopropane-1-carboxylate synthase (ACS), 1-aminocyclopropane-1-carboxylate oxidase (ACO), hexokinase (HK), lipoxygenase (LOX), malate dehydrogenase (MDH), endoglucanase (CEL), various transcription factors (TCP, MYB, EFR), and peroxidase (POD). ATAC-Seq analysis further revealed that LED treatment primarily regulated phenylpropanoid biosynthesis.

CONCLUSION

The results obtained in this study provide insights into the effects of LED light exposure on apricot fruits ripening. LEDs offer a promising approach for extending the shelf life of other fruits and vegetables.

Enhancement of the Physical and Functional Properties of Chitosan Films by Incorporating Galla chinensis Extract

Composite films based on chitosan (CS) incorporating Galla chinensis extract (GCNE) at different CS/GCNE weight ratios, which are both biodegradable and multifunctional, were fabricated using the solution-casting method. The FTIR analyses indicated that a good interaction was presented among the GCNE and CS through an intermolecular hydrogen bond. The incorporation of the GCNE improved the films' elongation at break, UV-light blocking, and decreased the moisture regain (from 16.68% to 10.69%) and water absorption (from 80.65% to 54.74%). Moreover, the CS/GCNE films exhibited a strong antioxidant activity (from 57.11% to 70.37% of DPPH and from 35.53% to 46.73% of ABTS scavenging activities) mainly due to the high content of phenolic compounds in the incorporated GCNE. The CS/GCNE film-forming solution coatings demonstrated their effectiveness in preserving the quality of postharvest mangoes, specifically by minimizing the change in the firmness, weight loss, titratable acidity, and total phenolic and ascorbic acids. These findings suggest that the multifunctional composite films possess a high application potential to preserve postharvest fruits.

Edible Coatings as a Natural Packaging System to Improve Fruit and Vegetable Shelf Life and Quality

In the past years, consumers have increased their interest in buying healthier food products, rejecting those products with more additives and giving preference to the fresh ones. Moreover, the current environmental situation has made society more aware of the importance of reducing the production of plastic and food waste. In this way and considering the food industry's need to reduce food spoilage along the food chain, edible coatings have been considered eco-friendly food packaging that can replace traditional plastic packaging, providing an improvement in the product's shelf life. Edible coatings are thin layers applied straight onto the food material's surface that are made of biopolymers that usually incorporate other elements, such as nanoparticles or essential oils, to improve their physicochemical properties. These materials must provide a barrier that can prevent the passage of water vapor and other gasses, microbial growth, moisture loss, and oxidation so shelf life can be extended. The aim of this review was to compile the current data available to give a global vision of the formulation process and the different ways to improve the characteristics of the coats applied to both fruits and vegetables. In this way, the suitability of compounds in by-products produced in the food industry chain were also considered for edible coating production.

Application of a Chitosan-Cinnamon Essential Oil Composite Coating in Inhibiting Postharvest Apple Diseases

The purpose of this study was to explore the film-forming properties of cinnamon essential oil (CEO) and chitosan (CS) and the effect of their composite coating on postharvest apple diseases. The results demonstrated that the composite coating exhibits favorable film-forming properties at CEO concentrations below 4% (v/v). The effectiveness of the composite coating in disease control can be attributed to two factors: the direct inhibitory activity of CEO against pathogens in vitro and the induced resistance triggered by CS on the fruits. Importantly, the incorporation of CEO did not interfere with the induction of resistance by CS in harvested apples. However, it is noteworthy that the inhibitory effect of the CS-CEO composite coating on apple diseases diminished over time. Therefore, a key aspect of enhancing the preservation ability of fruits is improving the controlled release properties of CEO within CS coatings. This will enable a sustained and prolonged antimicrobial effect, thereby bolstering the fruit preservation capabilities of the composite coatings.

A comprehensive review of intelligent packaging for fruits and vegetables: Target responders, classification, applications, and future challenges

Post-harvest fruits and vegetables are extremely susceptible to dramatic and accelerated quality deterioration deriving from their metabolism and adverse environmental influences. Given their vigorous physiological metabolism, monitoring means are lacking due to the extent that unnecessary waste and damage are caused. Numerous intelligent packaging studies have been hitherto carried out to investigate their potential for fruit and vegetable quality monitoring. This state-of-the-art overview begins with recent advances in target metabolites for intelligent packaging of fruits and vegetables. Subsequently, the mechanisms of action between metabolites and packaging materials are presented. In particular, the exact categorization and function of intelligent packaging of fruits and vegetables, are all extensively and comprehensively described. In addition, for the sake of further research in this field, the obstacles that impede the scaling up and commercialization of intelligent packaging for fruits and vegetables are also explored, to present valuable references.

Development and characterization of a novel active and intelligent film based on pectin and betacyanins from peel waste of pitaya (Hylocereus undatus)

In the present study, peel waste of pitaya (Hylocereus spp.) was used to develop a novel active and functional film. The film was developed with a combination of the white-fleshed pitaya peel pectin (WPPP) as a biopolymer and white-fleshed pitaya peel betacyanins (WPPB) as an active constituent, respectively. Furthermore, montmorillonite (MMT), a cheap and environmental-friendly silicate material, was introduced into film matrix as a filler to reduce the moisture sensitivity of the film. The effect of the incorporation of WPPB on the properties of WPPP/MMT films was investigated. The colorimetric response of WPPP/MMT/WPPB to pH and ammonia was examined, respectively. Moreover, WPPP/MMT/WPPB-2 was employed to monitor the freshness of shrimp. The color of the film changed from redness to reddish-brown, and further to brownness, echoing the shrimp turned from fresh to spoiled. Therefore, WPPP/MMT/WPPB-2 composite films showed promise for the applications in monitoring the freshness of shrimp.