Fresh-cut Apples Research Articles

Edible coating with Eugenia pyriformis leaf extract to control enzymatic browning in fresh-cut apples

Fruits and vegetables are an important part of a healthy and balanced diet. Fresh cut fruits consumption is increasing, however keeping the food quality when processed is a challenge for the food industry. When the food is processed, some enzymatic changes can occur, being that enzymatic browning is one of this important degradation suffered by fresh cut apples. One alternative to reduce the enzymatic browning is the use of edible coating with anti browning components as vegetal extracts rich in phenolic compounds. The aim of this paper was characterize Uvaia (Eugenia pyriformis Cambess) leaf extract, evaluate the effect of sodium alginate edible coating formulated with uvaia leaf extract against enzymatic browning in fresh cut apples (cv. Golden Delicious and Royal Gala) during 8 days of storage. Phenolic compounds as chlorogenic acid, caffeic acid and p-coumaric acid were identified in Uvaia methanolic leaf extract. Uvaia aqueous leaf extract presented ABTS IC50 of 0.77 ± 0.002 mg/mL, increasing 40.66% the edible coating antioxidant activity. Uvaia aqueous leaf extract controlled 80% of polyphenol oxidase activity from Golden Delicious apple and edible coating with extract reduced enzymatic browning. Sodium alginate edible coating with Uvaia aqueous leaf extract is an alternative to reduced enzymatic browning of fresh cut apple (cv. Golden Delicious).

Effects of pre-treatment with S-nitrosoglutathione-chitosan nanoparticles on quality and antioxidant systems of fresh-cut apple slices

In order to develop a new and effective fruit treatment technology, fresh-cut apple slices were treated with water, S-nitrosoglutathione (GSNO), chitosan, and S-nitrosoglutathione-chitosan nanoparticles (GSNO-CS) and then stored at 4 °C for 4 days to investigate the changes in the quality characteristics and the antioxidant biochemical system. The results indicated that GSNO-CS preserved the quality of fresh-cut apple slices more effectively compared to other treatments. Specifically, fresh-cut apple slices treated with GSNO-CS was detected the higher antioxidant enzymes activities, which was 1–7.2 times that of control samples, and the lowest reactive oxygen species content, which was 8.97%–58.97% of the control. In addition, GSNO-CS kept the surface color and weight of the apple slices in an effective way, and reduced the respiration rate of the apple slices to 21%–47% that of the control during storage. All the results of this study suggested that GSNO-CS treatment effectively preserved the quality and enhanced the antioxidant capacity of fresh-cut apple slices.

Aqueous ozone treatment inhibited degradation of cellwall polysaccharides in fresh-cut apple during cold storage

The effects of aqueous ozone (AO) treatment on the firmness, cellwall polysaccharide content, enzymatic activity, and gene expression of cell wall-degrading enzymes were investigated in fresh-cut apple during cold storage. AO treatment (1.4 mg L−1 for 5 min) delayed degradation of cellwall polysaccharides to reduce softening of fresh-cut apple. Water-soluble pectin content increased more slowly, while protopectin content, 4% KOH-soluble fraction, and cellulose content decreased at a lower rate in AO-treated fresh-cut apple compared with the control. However, no significant influence was shown on the 24% KOH-soluble fraction. AO treatment promoted increased pectin methylesterase activity, and distinctly inhibited β-galactosidase and α-arabinofuranosidase activities during storage. Polygalacturonase activity was not affected by AO treatment. Meanwhile, AO maintained the intactness of cell walls through repression of Mdβ-Gal and Mdα-Af transcript levels, thereby preserving the textural quality of fresh-cut apple during cold storage.

Optimization, characterization and evaluation of papaya polysaccharide-corn starch film for fresh cut apples

In this study, we prepared corn starch (CS) and papaya polysaccharide (PPs) films using the solution casting technique. A Box-Behnken experimental design was used to determine the effect of ethanol concentration, extraction duration, and material concentration during PPs extraction. The resulting films were characterized in terms of structural changes, physical, optical, mechanical, Fourier-transform infrared (FTIR) spectroscopy, and thermal properties. The results show that PPs-CS composite films have good antioxidant and moisturizing properties and general antibacterial performance. These results revealed that after adding PPs, the films exhibited a significant increase in swelling and tensile strength, while depicted a reduction in thickness, transparency, and solubility. SEM images revealed that PPs and CS are highly compatible; moreover, FTIR spectroscopy showed that intermolecular hydrogen bonding existed between CS and PPs, forming a compact film structure. Finally, the incorporation of PPs and CS influenced the shelf-life of fresh cut apples, with the edible film incorporated with PPs positively improving sensory acceptance of combined materials.

Prebiotic-alginate edible coating on fresh-cut apple as a new carrier for probiotic lactobacilli and bifidobacteria

The increased popularity of vegetarianism, lactose intolerance, and the high cholesterol content of dairy products are all factors that have recently increased the demand for non-dairy probiotic foods. This study aimed to evaluate the effect of probiotic supplementation of fresh-cut apple coated with alginate-prebiotic on its nutritional, safety, and sensory characteristics. Also, probiotic viability during refrigerated storage and after simulated gastrointestinal digestion (GID) was evaluated. A new non-dairy probiotic food was developed by adding prebiotics (oligofructose and inulin) and probiotic cultures (Lactobacillus rhamnosus and Bifidobacterium animalis subsp. lactis) to fresh-cut apple. Both probiotics successfully remained above 9.0 log CFU/g in the product after 8 days of storage. Also, high viability retention was achieved after GID with 7.8 and 8.0 log for L. rhamnosus and B. lactis, respectively, without significant effect of prebiotic addition. Microbiological and nutritional quality were maintained, however only those samples with prebiotics and B. lactis remained sensorially acceptable after 8 d. Furthermore, both probiotics exerted bactericidal effect against L. innocua inoculated on apple cubes with reductions higher than 1.8 log meanwhile, the effect on E. coli O157:H7 was less pronounced. Thereby, apple pieces coated with prebiotic-alginate solution constitute a promising alternative to design new carriers for probiotic bacteria.

Flavonoid enrichment of fresh-cut apple through osmotic dehydration-assisted impregnation

PurposeInclusion of bioactive compounds in food products is promising for developing novel functional food products. The feasibility of incorporating flavonoids and low-calorie sugar substitutes in fresh-cut apple through osmotic dehydration (OD) was investigated.Design/methodology/approachThe impregnation of quercetin and fisetin in apple cubes was tested. The effects of different osmotic agents, sucrose and sorbitol:mannose, on the water loss (WL) and sugar gain of the samples were studied at 25 and 40 °C for eight hours.FindingsTemperature was a significant factor in the mass transfer kinetics, that is to say, higher temperatures resulting in higher rates. The molecular weight of the solutes in the osmotic solution also affected the OD kinetics and flavonoids uptake, as well as the physico-chemical quality.Originality/valueOverall, the results indicate that OD using alternative low-calorie and health-promoting solutes can be an effective treatment to simultaneously enrich fresh-cut apples with senolytic flavonoids, therefore presenting a great potential for a novel functional food product.

Calcium ascorbate treatments to control the fresh-cut apple quality reduction when stored at high temperature

Calcium ascorbate treatments to control the fresh-cut apple quality reduction when stored at high temperature

Effect directed synthesis of a new tyrosinase inhibitor with anti-browning activity

The inhibition of enzymatic browning is an attractive target to elevate the quality of foods. The objective of this work is to describe a novel platform for the discovery of tyrosinase inhibitors, based on (a) one-pot preparation of a library of thiosemicarbazide compounds, (b) biological evaluation using tyrosinase TLC bioautography, (c) inhibitor identification via mass spectrometry coupled to bioautography. During these proof-of-concept experiments, the approach led to the straightforward identification of a new thiosemicarbazone with improved tyrosinase inhibition properties and fresh-cut apple slices antibrowning effect when compared to kojic acid. In conclusion, the platform represents an interesting strategy for the discovery of this type of inhibitors.

A difference of enzymatic browning unrelated to PPO from physiology, targeted metabolomics and gene expression analysis in Fuji apples

Abstract Browning is an important factor affecting the quality of fresh-cut apples, and studying this factor is valuable. Previous research has found that apple browning is due to an enzymatic reaction caused by polyphenol oxidase (PPO), which results in the darkening of apples through the oxidation of polyphenols to quinones. We screened two Fuji apple types, “flushed-skin color pattern” (Type P) and “striped-skin color pattern” (Type T) from bud mutation cultivars. Type P has slower browning rate than type T. Using physiology, targeted metabolomics and real-time quantitative PCR, we found that polyphenol-related parameters including PPO activities, total phenol contents and expression of five genes (MdF3H, MdPPO, MdUGT88F1/4, MdLAR and MdC4H) did not change during browning in both apple types. However, levels of hyperoside, peroxidase (POD), superoxide dismutase (SOD), hydrogen peroxide (H2O2), ascorbic acid (AsA) and expression of nine genes (MdPAL, MdCHS, MdCHI, MdANS, MdFLS, MdANR, MdUGT71K1s, MdTTG1 and MdMYB1) were higher levels in type P apples. Correlation analysis indicated that the browning was unrelated to total phenol and PPO activities. Browning index (BI) was negatively correlated with hyperoside, whilst malondialdehyde (MDA) and nine up-regulated genes were positively correlated. We therefore conclude that hyperoside may be the most critical indicator in apple browning. In summary, we found a difference of enzymatic browning unrelated to in Fuji apples. This research provides new insight into the phenomenon of fruit browning.

Mogućnosti i perspektive svježe narezanog voća i povrća na zagrebačkom tržištu

The fresh-cut fruits and vegetables (FCFV) are defined as products that have been trimmed and/or peeled and/or cut into 100% usable product that is bagged or pre-packaged to offer consumers a high nutrition, convenience and flavor while still maintaining its freshness. Fruits and vegetables (FV) are abundant with phytochemicals that indicate beneficial influence on human health when consumed frequently and as a part of daily diet. Healthy conscious consumers appreciate convenience of FCFV, but due to its extreme perishability sometimes their quality and safety may be questionable leading to its shortened shelf-life. Optimal processing as well as distribution conditions are imperative for prolonging their shelf-life. Hence, the prototype of vending machine (VM) for FCFV which could replace usual salad bars in food services and maintaining the highest hygiene criteria was constructed by funding of the BICRO-project and implemented at Faculty of Food Technology and Biotechnology University of Zagreb. In the first part of this study, performance of VM prototype in the cold storage of fresh-cut (FC) apple during 7 days was investigated and interest for FCFV by oral survey with Zagreb citizens was examined in the second part. Quality and sensory characteristics of FC apples stored in VM remained satisfactory for 4 days and microbial analysis showed that VM could provide a safe product for 7 days. Furthermore, the need for such device confirmed the tendency of consumers to choose their own FCFV combinations and purchase such products near the workplace. In general, market analysis proved increased consumers demand for FCFV.

MiRNA and Degradome Sequencing Identify miRNAs and Their Target Genes Involved in the Browning Inhibition of Fresh-Cut Apples by Hydrogen Sulfide.

Surface browning is the major limit for the shelf life of fresh-cut apples, and hydrogen sulfide (H2S) treatment can effectively inhibit the browning. However, the molecular mechanism on how fresh-cut apples respond to H2S was poorly understood. MicroRNAs (miRNAs) are a class of endogenous small noncoding RNAs, which regulate multiple crucial biological processes in almost all aspects of the life cycle. Herein, 12 small RNA libraries and one mixed degradome library were constructed from control and H2S-treated fresh-cut apples immediately after treatment (C0 and S0) and 6 d of storage (C6 and S6) at 4 °C. The results identified nine (three upregulated and six downregulated) and 10 (two upregulated and eight downregulated) differentially expressed miRNAs (DEmiRNAs) in S0 versus C0 and S6 versus C6, respectively. The target genes of DEmiRNAs were transcription factors and functional proteins. The miR156 targeting SPL, miR164 targeting NAC, miR319 targeting TCP4, GAMYB, and acyl-CoA-binding protein 4, and miR6478 targeting patatin-like protein 2 might play important roles in the browning inhibition of fresh-cut apples by H2S via regulating the ROS, phenylpropanoid, and lipid metabolism. The results give valuable information for further studying the role of miRNA in regulating browning processes and the underlying molecular mechanism of H2S treatment on browning inhibition.

Comparison between Hyperspectral Imaging and Chemical Analysis of Polyphenol Oxidase Activity on Fresh-Cut Apple Slices

The assessment of the quality of fresh-cut apple slices is important for processing, storage, market value, and consumption. Determination of polyphenol oxidase activity (PPO) in apples is critical for controlling the quality of the final product (i.e., dried apples and juices). Hyperspectral imaging (HSI) is a nondestructive, noncontact, and rapid food quality assessment technique. It has the potential to detect physical and chemical quality attributes of foods such as PPO of apple. The aim of this study was to investigate the suitability of HSI in the visible and near-infrared (VIS-NIR) range for indirect assessment of PPO activity of fresh-cut apple slices. Apple slices of two cultivars (cv. Golden Delicious and Elstar) were used to build a robust detection algorithm, which is independent of cultivars and applied treatments. Partial least squares (PLS) regression using the 7-fold cross-validation method and method comparison analysis (Bland–Altman plot, Passing–Bablok regression, and Deming regression) were performed. The 95% confidence interval (CI) bands for the Bland–Altman analysis between the methods were −4.19 and 13.11, and the mean difference was 3.7e−12. The Passing–Bablok regression had a slope of 0.8 and an intercept of 7.6. The slope of the Deming regression was 0.8 within the CI bands of 0.56 and 1.10. These results show acceptable performance and no significant deviation from linearity. Hence, the results demonstrated the feasibility of HSI as an indirect alternative to the standard chemical analysis of PPO enzyme activity.

Effectiveness of a pomegranate peel extract (PGE) in reducing Listeria monocytogenes in vitro and on fresh-cut pear, apple and melon

Pomegranate peel extract (PGE) is a new promising natural alternative control substance with large spectrum of activity against wide range of pathogenic microorganisms. In the present study, PGE was firstly investigated as natural antimicrobial against Listeria monocytogenes both in vitro and on fresh-cut fruits. The in vitro results showed quick and strong bactericidal and bacteriostatic activity against five different strains which were almost completely inhibited by the extract. Furthermore, it significantly decreased growth rate and maximum growth of all tested strains. In vivo trials, confirmed a strong antibacterial activity of the extract that significantly reduced the bacterial load on fresh-cut apple, melon and pear and maintained the population at low levels throughout the storage period (7 days). PGE at 12 g/l reduced L. monocytogenes by 1.24, 1.89, and 0.91 log units soon after treatment and by 3.81, 1.53, and 2.99 log units, after 7 days of storage on apple, pear and melon, respectively. This high antibacterial activity could be mainly related to the high content of polyphenols (ellagitannins) in the extract. Overall, results of this study suggest a potential industrial application of PGE to reduce the growth of the pathogenic microorganisms in fresh-cut fruit and ensure a microbial safety in case of contamination.

Cucumis metuliferus Fruit Extract Loaded Acetate Cellulose Coatings for Antioxidant Active Packaging.

A new active coating was developed by using Cucumis metuliferus fruit extract as antioxidant additive with the aim of obtaining an easy way to functionalize low-density polyethylene (LDPE) films for food packaging applications. Thus, an extraction protocol was first optimized to determine the total phenolic compounds and the antioxidant activity of CM. The aqueous CM antioxidant extract was then incorporated into cellulose acetate (CA) film-forming solution in different concentrations (1, 3 and 5 wt.%) to be further coated in corona-treated LDPE to obtain LDPE/CA-CM bilayer systems. CA and CA-CM film-forming solutions were successfully coated onto the surface of LDPE, showing good adhesion in the final bilayer structure. The optical, microstructural, thermal, mechanical and oxygen barrier performance, as well as the antioxidant activity, were evaluated. The active coating casted onto the LDPE film did not affect the high transparency of LDPE and improved the oxygen barrier performance. The antioxidant effectiveness of bilayer packaging was confirmed by release studies of Cucumis metuliferus from the cellulose acetate layer to a fatty food simulant. Finally, the LDPE/CA-CM active materials were also tested for their application in minimally processed fruits, and they demonstrated their ability to reduce the oxidation process of fresh cut apples. Thus, the obtained results suggest that CA-CM-based coating can be used to easily introduce active functionality to typically used LDPE at industrial level and enhance its oxygen barrier, without affecting the high transparency, revealing their potential application in the active food packaging sector to extend the shelf-life of packaged food by prevention of lipid oxidation of fatty food or by prevention fruit browning.

Storage quality of fresh-cut apples treated with yerba mate (Ilex paraguariensis)

Dipping fresh-cut fruits in antioxidant solutions is a useful method to avoid enzymatic browning. Yerba mate extracts have a high content of antioxidant compounds and could be a natural alternative to control browning and improve the bioactive properties of fresh-cut apples. Therefore, this study aimed to evaluate the performance of an antioxidant solution of yerba mate (1.2%), citric acid (0.9%) and ascorbic acid (1.0%) with water as control, on fresh-cut 'Granny Smith' apples during storage at 2°C (18days) and 10°C (15days) under MAP. Physicochemical characteristics, bioactive properties, sensory attributes, microbial quality as well as the gas composition within the packages were analyzed throughout storage. Samples from both treatments showed a slower quality loss at 2°C than at 10°C. The antioxidant solution increased the lag-phase of molds, mesophilic and psychrotrophic microorganisms stored at 2°C. The phenolic compounds of yerba mate together with ascorbic acid, not only increased the antioxidant capacity of the fresh-cut apples but also reduced the enzymatic browning at both temperatures, increasing the storage time in 2-5days with an acceptable appearance, when compared to control samples. The antioxidant solution containing yerba mate provided the fresh-cut apples with a higher content of healthy compounds throughout storage at both temperatures.

Browning inhibition on fresh-cut apple by the immersion of liquid endosperm from mature coconuts.

The application of natural antibrowning agents for fresh-cut products has been recently considered. This study manifested the efficiency of coconut liquid endosperm, coconut water (CW), from mature tall (cooking) coconut (C-CW) and yellow dwarf coconut (Y-CW) on browning inhibition of 'Gala' apple wedges during storage at 4 ± 1°C for 9days. The apple wedges were immersed in water (control), C-CW or Y-CW for 1min. The visual appearance, superficial colour attributes, browning pigment concentration, total phenols concentration, polyphenoloxidase (PPO) activity and reducing antioxidant capacity of apple wedges were monitored. Moreover, antioxidant activity of both C-CW and Y-CW was also observed. Antioxidant activity of Y-CW was higher than that of C-CW. Both of the CW immersions maintained visual appearance, whiteness and lightness values as well as delayed the increased yellowness and brownness values of hypanthium (flesh) and mesocarp (core) of apple wedges. The browning pigment concentration and PPO activity were obviously lowered by both CW immersions. Total phenols concentration and antioxidant activity of C-CW and Y-CW immersed apple wedges were higher than those of control samples. In conclusion, both of the mature coconut liquid endosperms are feasible natural agent inhibiting browning incidence of fresh-cut fruits during storage.

Use of Aloe Vera Gel-Based Edible Coating with Natural Anti-Browning and Anti-Oxidant Additives to Improve Post-Harvest Quality of Fresh-Cut ‘Fuji’ Apple

Recently, there is increasing use of edible and biodegradable films and packaging that are both environmentally friendly and functional for storage and market distribution. Fresh-cut ‘Fuji’ apples, harvested in an organic farm, were treated, using a spraying technique, with three new edible coatings based on Aloe vera gel (AVG—40% v/w) and in combination with natural additives: lemon essential oil (LEO—1% v/w) and hydroxypropyl methylcellulose (HPMC—0.1% v/w) and compared with untreated sample (CTR), the physicochemical and sensory characteristics and the proximate compounds were evaluated. During cold storage, weight loss, soluble solids content, and color of uncoated slices were reduced, while softening, ripening, browning, and acidity were accelerated. In contrast, the AVG/HPMC treatment significantly delayed the above parameters related to post-harvest quality loss, while the AVG/LEO treatment delayed the browning processes, maintaining an excellent color during cold storage. Concerning proximate compounds, the treatments did not alter their concentration in the fruit tissues. Sensory analyses revealed no detrimental effect on taste, aroma, or flavor. Our data evidenced the positive effect of Aloe vera gel in combination with LEO and HPMC on fresh-cut apple quality as an innovative and sustainable technique to maintain fresh-cut apple quality.

The effect of hot water, 1-MCP, and lovastatin on fresh-cut apples after long-term controlled atmosphere storage

This research was carried out over two years to determine the quality changes in fresh-cut apple slices processed after hot water, 1-methylcyclopropene 1-MCP , and lovastatin treatments followed by controlled atmosphere CA storage. Apples harvested at the optimum stage were immediately transferred to the postharvest laboratory by a refrigerated vehicle. Intact apples were exposed to three treatments: dipping into hot water 50 °C for 60 s , treating with lovastatin 1.25 mmol L-1 , and treating with 1-MCP 1 µL L-1 . Treated apples and the control group were stored in CA storage 2% O2 + 2% CO2 for 10 months. After long-term storage, the apples, sliced and packaged in plastic boxes, were stored at 0 °C and 90 ± 5% relative humidity RH for 14 days. Weight loss, soluble solid content, flesh firmness and color, titratable acidity, respiration rate, microbial count, and ethylene synthesis were determined during storage. As a result, a global beneficial effect of 1-MCP on sliced apples was observed, although its affirmative effect on ethylene synthesis and respiration rate vanished after 10 months of storage. 1-MCP-treated slices had better results in terms of microbial count, flesh firmness, external appearance, and weight loss compared to other applications. Lovastatin decreased the ethylene synthesis and respiration rate and was the best treatment to maintain the flavor of apple slices. Hot water and control treatments gave similar results for fruit quality and microbial activity. After long-term cold storage 10 months in CA, fresh-cut apple slices could be stored for 7 days with good quality at 0 °C and 90 ± 5% RH.

The effect of UV-C and electrolyzed water on yeasts on fresh-cut apple at 4 °C

The growth of a yeast mixture, Candida sake, Hanseniaspora uvarum, Pichia fermentans, Metschnikowia pulcherrima, on fresh-cut apple (Royal gala), at 4 °C, was studied, as well as the reduction of yeasts using Ultraviolet-C (UV–C), acidic (AEW) and neutral (NEW) electrolyzed waters, and sodium hypochlorite (SH). Apple portions were contaminated then disinfected with UV-C (2.5–10 kJ/m2), AEW, NEW and SH (100 ppm). During 9 days at 4 °C, yeasts growth rate was 0.34 day−1 and the stationary phase occurred after 6 days (7.42 LogCFU/g). The initial microbial reduction and the half-life time values, using the inverse hyperbola model, ranged from 1.72 to 1.81 LogCFU/g and 6.52–11.70 day (UV–C), or 0.91 to 1.96 LogCFU/g and 0.68–4.38 day (chemical treatments), where SH was the least efficient (0.92 LogCFU/g and 2.96 day). The most effective treatment was UV-C (7.5 and 10 kJ/m2). The yeasts psychrotrophic profile highlights the importance of avoiding contamination/cross-contaminations in all processing.

Surface plasma discharges for the preservation of fresh-cut apples: microbial inactivation and quality attributes

Sustainable and cost effective food preservation techniques are of industrial, environmental and public health significance globally. A promising means for the gentle but efficient sanitation of foods is the application of cold atmospheric plasma. Here, the preservation of fresh-cut apples was investigated using a gas phase surface discharge plasma (SDP) reactor within an exposure chamber. Results show that the microbial load reduction of the fresh-cut apples was found to be strongly dependent on the storage time and preservation method, e.g. refrigeration (control), SDP-room temperature and SDP-refrigeration (SDP-RF). After 6 d of storage, the microbe load on the apple pieces for the SDF-RF treated groups was found to be significantly lower compared to the refrigeration-stored (4 °C) and the SDP only-processed groups, with the lowest bacterial load on the 120 s SDP-RF stored apple pieces (1.76 CFU g−1). Furthermore, the effects of the preservation method on the quality attributes (weight loss, firmness, and physical appearance), and the surface chemistry directly after cutting and SDP processing, as well as the activities of polyphenol oxidase and peroxidase after the different duration of storage were evaluated. This study successfully demonstrates the feasibility of SDP for the effective preservation of fresh-cut apples and contributes to the fundamental understanding of surface plasma-induced effects on the microbial inactivation and postharvest quality of fresh-cut fruits.