Fresh-cut Fruits Research Articles

The Use of Nanocellulose in Edible Coatings for the Preservation of Perishable Fruits and Vegetables

The usage of edible coatings (ECs) represents an emerging approach for extending the shelf life of highly perishable foods, such as fresh and fresh-cut fruits and vegetables. This review addresses, in particular, the use of reinforcing agents in film-forming solutions to tailor the physicochemical, mechanical and antimicrobial properties of composite coatings. In this scenario, this review summarizes the available data on the various forms of nanocellulose (NC) typically used in ECs, focusing on the impact of their origin and chemical or physical treatments on their structural properties (morphology and shape, dimension and crystallinity) and their functionality. Moreover, this review also describes the deposition techniques of composite ECs, with details on the food engineering principles in the application methods and formulation optimization. The critical analysis of the recent advances in NC-based ECs contributes to a better understanding of the impact of the incorporation of complex nanoparticles in polymeric matrices on the enhancement of coating properties, as well as on the increase of shelf life and the quality of fruits and vegetables.

Assessment of toxic effect ofCentella asiaticaextract and its application as natural preservative in fresh‐cut mango, pear and cabbage

The study determined the toxicity and Centella asiatica extract’s efficiency as food preservative in fresh-cut fruits and vegetables (FCFV) during room temperature displayed (RTD; 22 ± 1℃) and chilled storage (CS; 4 ± 0.5℃). In toxic assessment, the LC50 extract was 597.72 mg/ml, indicating as nontoxic to consume. Listeria monocytogenes (6.40 log CFU/ml), Staphylococcus aureus (6.46 log CFU/ml), and Salmonella Typhimurium (6.92 log CFU/ml) were respectively inoculated in mango, pear, and cabbage. The survived population of bacteria varied from 4.87 to 6.87 log CFU/g (RTD-FCFV) and 3.46 to 4.92 log CFU/g (CS-FCFV). This indicates that the extract had no effects on pathogenic bacteria at all during RTD. Browning indexes in extract-treated pear (RTD: 7.15; CS: 16.20), mango (RTD: 9.40; CS: 16.39), and cabbage (RTD: 4.72; CS: 3.96) were recorded. In short, chilling and prolonged extract-contact periods could effectively retard browning of FCFV but less effective for bacteria reduction in FCFV at 250 mg/ml extract. Practical applications Long-term consumption of synthetic preservatives will cause adverse health effects to consumers. The application of preservatives derived from natural plant resources is a potential replacement for synthetic preservatives. Despite Centella asiatica extract was proven to be a potent antimicrobial and antioxidant agent but without applied to any food models in existing research. Therefore, C. asiatica extract was used as a natural preservative to improve microbial inhibition and to reduce browning formation in fresh-cut fruits and vegetables (FCFV). Based on experimental findings, C. asiatica extract could exhibit less effectiveness in microbial reduction but able to reduce browning and discoloration in FCFV under room temperature displayed or chill storage without affecting original food appearance and color.

Transcriptome profiling for pericarp browning during long-term storage of intact lotus root (Nelumbo nucifera)

Lotus root (Nelumbo nucifera) is an edible rhizome that the consumption/production has continuously increased as more consumers demand convenient and ready-to-eat foods. However, the processing, storage, and transportation of fresh-cut fruits and vegetables promotes physiological deterioration, such as browning, which leads to a reduction in the value of the product. This study aimed to reduce the browning of lotus root pericarps during long-term storage and long-distance transport, and to clarify the functions of unigenes and browning-associated metabolic pathways using RNA-sequencing techniques. Intact lotus root cv. ‘Kanasumi No.34’ browning decreased after the roots were packed along with an anti-browning solution. Over 200 million short single-end reads were mapped onto the N. nucifera consensus coding sequence set. The significantly differentially expressed genes (DEGs) were identified. Based on the Uniprot, GO, and KEGG databases, secondary metabolism, lipid metabolism, and redox state genes were significantly upregulated in the un-packed and packed with water treatments compared to after harvest sample. Additionally, 16 expected DEGs (e.g., PPO, PAL, POD, CHS, PDCR, and SOD), which are affected by browning development, were differentially regulated in lotus root pericarp. The gene expression data presented in this study will help elucidate the molecular mechanism underlying browning development in intact lotus root during long-term storage. The results may also inform future research on improving the post-harvest shelf life of lotus roots’.

Transcriptomic analysis reveals key genes associated with the biosynthesis regulation of phenolics in fresh-cut pitaya fruit (Hylocereus undatus)

Wounding stress induces phenolic accumulation in pitaya fruit (Hylocereus undatus). This study aimed to elucidate the possible molecular mechanism underlying the wound-induced phenolic biosynthesis in fresh-cut pitaya fruit based on transcriptomic and bioinformatic analysis. Wounding stress induced the activation of metabolic pathways associated with phenolic biosynthesis, including secondary metabolism such as phenylpropanoid pathway and flavonoid pathway, signaling molecules metabolism such as ethylene, reactive oxygen species and jasmonic acid, and primary metabolism such as glycolysis, pentose phosphate pathway and shikimate pathway. Moreover, weighted gene coexpression network analysis and evolutionary relationship analysis revealed that 1 HuMYB, 3 HubHLHs, 7 HuAP2-EREBPs could be identified as putative transcription factors participating in the regulation of wound-induced phenolic biosynthesis in pitaya fruit. These findings validated previous study that wounding stress induces the conversion of hexose pool to supply essential carbon skeletons for the phenolic accumulation in fresh-cut pitaya fruit in transcriptional level and provide important and useful genetic information for further studies on the functions of transcription factors in wounding response in pitaya fruit.

Development of active packaging film from sodium alginate/carboxymethyl cellulose containing shallot waste extracts for anti-browning of fresh-cut produce

Owing to growing concerns about making pollution-free sustainable environment by reducing the dumping of agricultural waste and convert it into valuable product is a key to carry out the present study. The ultimate goal of this study is to convert shallot onion wastes (SOWs) into active packaging and evaluating the anti-browning effect due to the SOWs holding rich polyphenols and antioxidants. The active packaging film was fabricated by using sodium alginate (SA) and carboxymethyl cellulose (CMC) along with shallot onion waste extract (SOWEs) such as peel and stalk at 0.2% and 0.5% concentration. The film made with SA/CMC/SOWEs had good physical, mechanical, optical and barrier property, higher phenolic and antioxidant activity compared to control. In addition, the effect of SA/CMC/SOWEs film packaging on anti-browning and quality of fresh-cut apple and potato stored at 4 °C was studied. The results show the SA/CMC/SOWEs film had better effect on controlling browning index in fresh-cut apple and potato over the storage of 12 days and 5 days. This study concludes that the SA/CMC film developed with shallot stalk extract can be used for wrapping of fresh-cut fruits and vegetables. It also prevents browning and maintains the overall quality than control and shallot peel incorporated film.

Transcriptome profiling reveals potential genes involved in browning of fresh-cut eggplant (Solanum melongena L.)

Fresh-cut processing promotes enzymatic browning of fresh fruits and vegetables, which negatively affects the product appearance and impacts their nutrition. We used RNA-sequencing to analyze the transcriptomic changes occurring during the browning of fresh-cut eggplant fruit samples from both browning-sensitive and browning-resistant cultivars to investigate the molecular mechanisms involved in browning. A total of 8347 differentially expressed genes were identified, of which 62 genes were from six gene families (i.e., PPO, PAL, POD, CAT, APX, and GST) potentially associated with enzymatic browning. Furthermore, using qRT-PCR, we verified 231 differentially regulated transcription factors in fresh-cut eggplant fruits. The enzyme activities of PPO, POD, PAL, and CAT in ‘36’ were significantly higher than those of ‘F’ fresh-cut for 15 min. Both PPO and POD play a major role in the browning of eggplant pulp and might therefore act synergistically in the browning process. Meanwhile, qPCR results of 18 browning related genes randomly screened in 15 eggplant materials with different browning tolerance showed variant-specific expression of genes. Lastly, gene regulatory networks were constructed to identify the browning-related genes. This work provides a basis for future molecular studies of eggplants, and lays a theoretical foundation for the development of browning-resistant fresh-cut fruits and vegetables.

Explanation of laws and regulations on fresh-cut fruits and vegetables

Explanation of laws and regulations on fresh-cut fruits and vegetables

γ-Aminobutyric acid (GABA) concentrations in relation to antioxidants in fresh-cut fruits and vegetables

<b>γ</b>-Aminobutyric acid (GABA) concentrations in relation to antioxidants in fresh-cut fruits and vegetables

Application of chitosan-gelatin active film with ethyl pyruvate on quality of fresh-cut pitaya fruit

Application of chitosan-gelatin active film with ethyl pyruvate on quality of fresh-cut pitaya fruit

Use of Centella asiatica extract in reducing microbial contamination and browning effect in fresh cut fruits and vegetables during storage: A potential alternative of synthetic preservatives

The study was focused on the effectiveness of Centella asiatica extract in microbial reduction and retarding browning formation of the samples obtained from fresh-cut fruits and vegetables (FCFV) during room temperature displayed (RTD) and chilled storage (CS). The microbial and color analyses were done in hour-basis (room temperature displayed) and daily basis (chilled storage). Candida albicans (6.77 log CFU/mL), Bacillus cereus (6.34 log CFU/mL), Escherichia coli O157:H7 (6.46 log CFU/mL) and Aspergillus niger (5.34 log CFU/mL) were specifically inoculated in apple, potato, lettuce, and pineapple, respectively. In room temperature displayed samples, the population of survival microorganisms ranged from 4.44 to 6.90 log CFU/g. In chilled stored samples, only A. niger was survived in chilled pineapple (3.00 log CFU/g) when storage end. Browning indexes in room temperature displayed and chilled stored samples ranged from 8.06 to 9.26 and 5.00 to 12.68, respectively. In short, low temperature and sufficient extract-treated periods may effectively inhibit microbial growth and browning index to prevent quality deterioration of fresh-cut fruits and vegetables.

Effects of modified atmosphere and sugar immersion on physiology and quality of fresh-cut 'Braeburn' apples

Fresh-cut fruits are highly perishable and show a short shelf life. Therefore, storage in sugar syrup is commercially used to delay undesirable metabolic changes and to prevent browning. Investigations on the effects of syrup application on volatile organic compounds (VOCs), important for the consumers’ acceptance, are rare. It is, however, known that low O2 availability, as found in fruit slices after immersion, may result in the formation of unwanted off-odour. This negatively affects the sensory quality of fresh-cuts. In the present study, fresh-cut 'Braeburn' apples were comparatively stored in air, in three modified atmospheres (O2: 10, 5 and approx. 0 %; CO2: 10, 15 and 20 %) or in sugar syrup (20 % sugar content). Relevant quality, physiological and microbiological parameters were evaluated on days 3, 6 and 10 of storage. Particular focus was laid on the evaluation of VOC emission to indicate biosynthetic responses that affect aroma-relevant VOCs. Atmospheric storage of apple slices, among others, increased the emission of ethyl acetate, which may create off-odour and negatively affects the customers’ acceptance. In contrast, syrup-immersion of apple slices resulted in a pronounced loss of aroma but prevented the occurrence of off-odour. The results indicated metabolic changes, which were independent of O2 availability. High CO2 or VOCs concentrations in the fruit tissue may inhibit esterification or may induce a feedback inhibition of VOC synthesis.

Combined Hurdle Technologies Using UVC Waterproof LED for Inactivating Foodborne Pathogens on Fresh-Cut Fruits.

This study investigated the combined bactericidal efficacy of slightly acidic electrolyzed water (SAEW), fumaric acid (FA), and ultravioletC waterproof light-emitting diodes (UVC W-LED) for the control of Staphylococcus aureus and Listeria monocytogenes in fresh-cut fruits. Cherry tomato, grape, apple, and pineapple were inoculated with S. aureus and L. monocytogenes and then washed with 30 ppm SAEW containing 0.5% FA in a container equipped with two UVC W-LEDs. Behaviors of S. aureus and L. monocytogenes and quality properties of fresh-cut fruits were monitored after storage at 10 °C and 15 °C for 7 days. The most effective reductions of S. aureus (1.65 log CFU/g) and L. monocytogenes (2.63 log CFU/g) were observed in the group with the combined treatment of SAEW + FA and UVC W-LED. At 10 °C and 15 °C, populations of both pathogens in the combined treatment group were lower than those in a control. Combined treatment showed no negative effect on moisture retention in the fruit. Moreover, visual changes were less significant than in the control. These results demonstrate that the combined treatment can improve the microbial safety and the quality of fruits. If it is properly used in the sanitizing step of the fresh produce industry, a positive effect can be expected.

Differences in Physicochemical Characters of Fresh-Cut Mango, Mangosteen and Rambutan Due to Calcium Chloride Application

The effect of the application of calcium chloride on the physicochemical changes of fresh-cut tropical fruits during storage processes was evaluated.

Combination of Edible Coatings Containing Oregano Essential Oil Nanoemulsion and Pulsed Light Treatments for Improving the Shelf Life of Tomatoes

Edible coatings (ECs) have attracted increasing attention in the last years as a simple yet effective approach to increase the storability of perishable foods, such as fresh or fresh-cut fruits and vegetables, contributing to maintaining their quality by reducing respiration rate and water loss. The incorporation of antimicrobial agents, such as essential oils, was reported to add also antimicrobial properties to the coatings, through the controlled release of the antimicrobial compounds on the food surface, contributing to further reduce microbial growth over extended periods of storage. Pulsed light (PL) treatments have been widely investigated as non-thermal processes for superficial decontamination of food and food-contact surfaces, because of their ability to cause, through a short exposition, a significant reduction in the microbial population. Therefore, the combination of ECs and PL treatments represents a promising hurdle approach in food preservation, for extending the shelf life of fresh products. ECs in combination with optimum PL treatment condition (4 J/cm2) improved the quality of tomato fruits in terms of reducing the growth of the endogenous flora, as well as of preserving the quality attributes (pH, total soluble solids, and color) over a 15-d storage at room temperature.

Pomegranate Peel Powder as a Food Preservative in Fruit Salad: A Sustainable Approach.

This study aimed to assess the potential of pomegranate peel powder as a natural preservative. Its effects were tested on fruit salad quality decay during refrigerated storage. Nectarine and pineapple, equally portioned in polypropylene containers and covered with fructose syrup, were closed using a screw cap in air, with and without the addition of a by-product peel powder. Specifically, amounts of 2.5% and 5% (w/v) of pomegranate peel powder were put into each container. Both the microbiological and sensory qualities of the fruit salad were monitored during storage at 5 °C for 28 days. The results demonstrated that the fruit salad with the by-products showed lower counts of total mesophilic bacteria, total psychrotrophic microorganisms, yeasts, and lactic acid bacteria compared to the control, thus confirming the recognized antimicrobial properties of pomegranate peel. The other interesting finding of this study is that the addition of the investigated by-product in fruit salad did not worsen the main sensory attributes of fresh-cut fruit. Therefore, these preliminary results suggest that pomegranate peel powder has potential applications as a natural preservative in the fresh-cut food sector.

Design, synthesis, molecular modeling, and biological evaluation of novel kojic acid derivatives containing bioactive heterocycle moiety as inhibitors of tyrosinase and antibrowning agents

Tyrosinase plays an important role in melanin biosynthesis and enzymatic browning of fresh-cut fruit and vegetables. To discover potent tyrosinase inhibitors and antibrowning agents, a series of novel kojic acid derivatives containing bioactive heterocycle moiety (4a-4l) were designed and synthesized. Thereinto, 4d displayed the most potent tyrosinase inhibitory activity with IC50 of 3.23 ± 0.26 μM and behaved as a competitive inhibitor with a Ki of 1.96 μM, compared to kojic acid (IC50 = 32.23 ± 2.01 μM). Besides, copper-chelating assay, fluorescence spectrum quenching experiment, ANS-binding fluorescence quenching analysis, and molecular modeling studies indicated that 4d may inhibit tyrosinase activity by chelating with copper ions in the active site of tyrosinase. Furthermore, 4d exhibited low cytotoxic activity and significant antibrowning effects.This study suggests that these compounds may serve as lead molecules for developing novel tyrosinase inhibitors and antibrowning agents.

Low molecular weight fucoidan prepared by fucoidanase degradation – A promising browning inhibitor

Low molecular weight (MW) fucoidans have been proved with excellent tyrosinase inhibitory activity, which may proposed as a potential anti-browning ingredient for fruit and vegetable fresh-keeping agent. This study was conducted to obtain a low MW fucoidan fraction with high tyrosinase inhibitory capacity from Laminaria japonica crude fucoidan by fucoidanase degradation and to preliminary explore its type of tyrosinase inhibition and the application in browning inhibition of fresh-cut fruit. Firstly, the wild fucoidan-degrading strain, Flavobacteriaceae RC2-3, was mutated by UV irradiation and the fucoidanase production was improved by 40.5%. Fucoidan, which degraded by purified fucoidanase for 2 h, presented favourable tyrosinase inhibitory ability and were then separated by ultrafiltration. The fucoidan fraction with MW below 5 kDa (FF5) demonstrated the best tyrosinase inhibitory effect and shown obvious browning inhibition of fresh-cut apple slices. The inhibitory kinetics revealed that FF5 was a quite effectively competitive inhibitor of tyrosinase. The results of this study suggested that FF5 could be used as a promising browning inhibitor in the preservation of fruits and vegetables.

The use of electrolyzed water as a disinfectant for fresh cut mango

The consumption of fresh-cut fruit is attributed to the health and convenience benefits of consumers. However, reports about associated-microorganism diseases have aroused the consumer's interest. Chlorine-based compounds are the classic method for the microbiological control. These compounds have been used to sanitize fruits and vegetables in the minimal processing industry worldwide, but they react with the organic matter present in the water that leads to the formation of potentially cancerous chlorinated compounds. Aiming to develop alternative technology to sodium hypochlorite, this study evaluated treatment with neutral electrolyzed water (NEW) on microbiology, quality and sensory parameters of fresh-cut mangoes. ‘Tommy Atkins’ mangoes were processed into cubes and treated by immersion in NEW solutions (0, 75, 150, 225 and 300 mg L−1) or chlorine-based product at 200 mg L−1, and then, stored at 3 ± 2 °C, 85 ± 5% RH for 0, 6 or 12 days. The microbiota of fresh-cut mangoes was reduced by NEW treatments similarly as observed by sanitization with commercial product. Nutritional components as vitamin C, carotenoids and phenolics were preserved by NEW treatments or commercial chlorine. Concerning the sensory aspects, the NEW at150 mg L−1 presented the same good acceptability as observed for commercial chlorine and even lower off-flavor intensity than this chlorine-based sanitizer. Fresh-cut mangoes treated with NEW at different concentrations showed equivalent microbiological and quality parameters to the mango treated with commercial sanitizer, which allow to provide that electrolyzed water is a viable alternative to chlorine-based compounds as a disinfectant, considering the lower adverse impact on the environment and possibly on human health.

EFFECT OF CHEMICAL AND THERMAL TREATMENTS ON INHIBITION OF PEROXIDASE ACTIVITIE OF PURPLE SKIN EGGPLANT (SOLANUMMELONGENA L.)

Peroxidase (POD) associated with the browning of fresh-cut fruits and vegetableswas extracted from purple skin eggplant(Solanum melongena L.) and characterised using reliable spectrophotometric methods. Maximal POD activity was found at 35 °C and pH 6.0 with guaiacol as the substrate. The enzyme was stable at his optimal temperature (35 °C) and hisat pH stability was in the range of 5.6 - 6.6.Peroxidase retained its full activity in the presence of ion K+, Cu2+, Na+, Pb2+ and Ba2+ but were inhibited strongly by the ion Fe2+ and Mg2+ and the reducing agents as sodium thiosulfateand ascorbic acid. Effect of heattreatment on eggplant peroxidase showed that D-values decreased with increasing temperature, indicating faster peroxidase inactivation at higher temperatures.At 60 °C, the D-values ranged from 20.42 to 54.24 min. Hence, heat treatment at 60 °C for 30 min reduced browning of eggplant fruit.These data can be used to predict prevention of browning in the purple skin eggplantby thermal inactivation and the use of chimical agents onthe enzyme.

Survival and transcriptomic response of Salmonella enterica on fresh-cut fruits

Salmonella enterica is frequently implicated in foodborne disease outbreaks associated with fresh-cut fruits. In the U.S., more than one third of fruit-related outbreaks have been linked to two S. enterica serotypes Newport and Typhimurium. Approximately 80% of fruit-related human salmonellosis cases were associated with tomatoes, cantaloupes and cucumbers. In this study, we investigated the population dynamics of S. Newport and S. Typhimurium on fresh-cut tomato, cantaloupe, cucumber and apple under short-term storage conditions. We further compared the transcriptomic profiles of a S. Newport strain on fresh-cut tomato and cantaloupe using high-throughput RNA-seq. We demonstrated that both S. enterica Newport and Typhimurium survived well on various fresh-cut fruit items under refrigeration storage conditions, independent of inoculation levels. However, S. enterica displayed variable survival behaviors on different types of fruits. For example, at 7 d storage, the population of S. enterica reduced less than 0.2 log (p > 0.05) on fresh-cut tomato and cantaloupe, in contrast to ~0.5 log (p < 0.05) on cucumber and apple. RNA-seq analysis suggested that S. enterica mediates its survival on fresh-cut fruits through differentially regulating genes involved in specific carbon utilization and metabolic pathways. Several known bacterial virulence factors (e.g., pag gene) were found to be differentially regulated on fresh-cut tomato and cantaloupe, suggesting a link between the events of food contamination and subsequent human infection. Findings from this study contribute to a better understanding of S. enterica survival mechanisms on fresh-cut produce.