Uncoated Fruits Research Articles

Teknik Edible Coating dengan menggunakan Campuran Gel Lidah Buaya dan Ekstrak Daun Psidium guajava L. untuk Mempertahankan Sifat Fisikokimia Buah Jambu Biji

The synthetic chemicals is a common substance used to extend the shelf life of postharvest fruit. But it can have health impact. The use of edible coatings from natural ingredients has begun to be developed. Modification of aloe vera gel by guava leaf extract as the edible coating to increase guava fruit shelf life has not been reported yet. Guava fruit coated by several compositions of aloe vera gel and guava leaf extract have been carried out. Observations on physichochemical in fruit on the days 0, 3, 6, 9, 12 and 15 were evaluated. The best quality found on guava fruit treated with the compotition of aloe vera gel:ethanol guava leaf extract: CMC:glycerol (90: 5:0.25: 0.5) on the day 15. It had a weight loss of 9.88%, a spoilage of 3.33%, the decrease of water content 11.61%, titratable acidity 0.5%, total antioxidant 1.08 mg AA/g FW, total phenolic 0.51 mg GAE/g FW, and increase of total dissolved solids 3.01 oBrix. This result was significantly better than the uncoated fruit. It can be concluded that guava leaf extract can be used to maintain the physicochemical properties during storage.

Postharvest Application of Aloe Vera Gel Improved Shelf Life and Quality of Strawberry (Fragaria x ananassa Duch.)

Strawberry is highly appreciated for its aroma and texture, but rapid detrimental changes lead to decay and loss of quality in strawberries, which are the main reasons for huge economic losses. To tackle this major concern, this research focused on assessing the efficacy of edible coatings based on aloe vera (AV) gel to maintain quality parameters and postharvest storage of strawberries. Fruits were coated with gel containing one of five different concentrations of AV gel (0%, 20%, 40%, 60% and 80%) and stored at 1 °C and 95% relative humidity (RH) for up to 20 days. The weight loss, total soluble solids and malondialdehyde content was higher in untreated fruits, whilst these parameters were reduced in treated fruits. The AV gel treated fruits also maintained firmness, titratable acidity, ascorbic acid and total antioxidant activity, whereas, a significant decrease in these parameters was observed in untreated fruits. Furthermore, AV gel coated fruits had better superoxide dismutase, catalase and ascorbate peroxidase activities than uncoated fruits. Additionally, AV gel coatings reduced the rate of loss of total phenolic and flavonoid contents during storage. Consequently, it is concluded that AV gel edible coating is recommended for improving postharvest life and for maintaining maximum quality characteristics of strawberry stored for 20 days stored at 1 °C and 95% RH. Among all treatments, 80% AV gel revealed the best results in maintaining the overall fruit quality and delaying ripening throughout the storage period

Quality Preservation of Ready-to-Eat Prickly Pears by Peels Recycling.

In the current study, prickly pear peel was advantageously recycled to preserve fruit quality. Specifically, the investigated by-products were transformed into powder and then loaded into an alginate-based solution to be applied as coating to peeled prickly pears, to give an example of sustainable minimally processed fruit. For comparison, uncoated fruit, and coated prickly pears without any powder were also prepared. During storage at refrigerated temperature, coated and uncoated samples were tested for weight loss, microbial and fungal proliferation, as well as for sensory quality acceptance. The results were interesting because great differences were found between coated and uncoated fruit, in that coating the fruit delayed weight loss and spoilage, compared to uncoated fruit. Between the simple coating and the coating with peel powder, slight differences were recorded in favor of the peel-enriched coating. In fact, it allowed the promotion of better fruit preservation, and sensory quality. Therefore, prickly pear peels, that represent abundant by-products during prickly pear processing, could be advantageously recycled to preserve fruit quality.

Utilization of Aloe vera gel and Acalypha indica. L leaf extract as edible coating to increase the shelf life of guava (Psidium guajava. L) fruit

The technology that is commonly used to control postharvest pathogen attacks is coating with synthetic chemicals, but this has an unfriendly impact on the environment and consumers. Coating with A. vera L gel and plant extracts is a natural way to extend shelf life and maintain postharvest quality. The research was focused on finding the composition of guava fruit coating with A. vera. L gel and A. indica. L leaf extract that provided physicochemical properties with optimal quality during storage. Parameters tested were weight loss, percent decay, moisture content, total dissolved solids and total titrated acid from guava fruit. The coating composition that gives the best guava fruit quality with a storage time of 15 days were 85% A. vera gel, 10% A. indica. L leaf extract, 0.025% Carboxy Methyl Cellulose (CMC) and 0.5% glycerol. The guava fruit coated with this composition had a weight loss of 11.19%, moisture content of 57.15%, a spoilage of 3.33%, a total dissolved solids of 7.67 oBrix and a total titrated acid of 1.90%. This value was better than uncoated fruit with weight loss of 30.48%, moisture content 28.42%, spoilage 14.44%, total dissolved solids 12.33 oBrix and total titrated acid 0.40%.

Soursop fruit storage: Edible coating based on Hibiscus sabdariffa mucilage

Soursop fruit (Annona muricata L.) is a crop of important economic value for the state of Nayarit, however, it has a fast ripening that causes a short shelf life. Several post-harvest handling techniques have been applied to reduce its metabolic processes, such as refrigeration, the use of 1-methylcyclopropene (1-MCP) and controlled and modified atmospheres. In recent years, polysaccharide-based coatings have been applied to fruits. The aim of this research was to evaluate the physicochemical changes of soursop fruits coated with hibiscus calyx mucilage (2%), stored at 22 °C and 15 °C. Weight loss, firmness, pH, total soluble solids, acidity and colour were evaluated. Results for coated fruits stored at 15 °C showed lower weight loss (6.4%), lower firmness (29.7 N), higher TSS concentration (10.4 °Bx) and lower acidity (0.38%) compared to uncoated fruits. Coating with hibiscus mucilage and storage at 15 °C for four days decreased fruit weight loss. It was also observed that storage under these conditions allows a lower concentration of total soluble solids and organic acids. The coatings did not intervene in the decrease of fruit peel colour. Key words: coating, mucilage, soursop, postharvest. Introduction Mexico is the world's leading producer of soursop, with a national production of 30, 790 T in 2019. In this sense, the state of Nayarit was the largest producer of soursop with 23,230 T (Servicio de Información Agroalimentaria y Pesquera [SIAP], 2020). Soursop production contributes to the economic growth of Nayarit; however, there is a problem in the handling of the fruit due to the high respiration rate and ethylene production leading to softening of the fruit, resulting in a short post-harvest shelf life (Balois-Morales et al., 2019). Nayarit does not have an adequate postharvest system, which leads to inadequate fruit handling during handling (Jiménez-Zurita et al., 2016), causing production losses (Tovar-Gómez et al., 2011). Therefore, there is interest in investigating postharvest technologies that allow prolonging shelf life while maintaining the nutritional quality of the fruit (Moreno-Hernández et al., 2014). As an alternative to improve postharvest handling and maintain the quality of fruit and vegetable products, the use of edible coatings has been implemented (Park et al., 2014). Edible coatings based on polysaccharides have gained importance because they create a modified atmosphere through a semi-permeable layer in the fruit that allows gas exchange, reducing metabolic processes and prolonging the postharvest life of the fruit (Solano-Doblado et al., 2018). Among the polysaccharides of interest, mucilages have been used due to their highly branched structure, complex polymeric and hydrocarbon nature that allows modifying the rheology of a solution (Dugarte et al., 2019). Coatings made from mucilage allow a decrease in weight loss, delay in the concentration of total soluble solids, as well as colour improvement (Zambrano et al., 2017). In the above context, hibiscus mucilage could be used as a material for the preparation of an edible coating to prolong the shelf life of fruits. With this in mind, the effect of hibiscus mucilage-based coating (2%) on physicochemical changes during postharvest storage was evaluated in this study.

Carnauba wax nanoemulsion applied as an edible coating on fresh tomato for postharvest quality evaluation

Edible coatings to extend the shelf life and preserve the quality of fruit and vegetables are highly demanded nowadays. Recently, plant-based edible coatings have gained importance in the context of sustainability, which in combination with suitable top-down process can render “greener” nanoemulsions with optimized properties. Herein we developed a carnauba wax nanoemulsion (CWN) by using a high-pressure processing to be applied as an edible coating for fruit and vegetables. The as-developed nanoemulsion properties were compared to conventional carnauba wax emulsion (CWM), where CWN showed particle size diameter of 44 nm and narrow distribution, while CWM displayed larger particles and wider size distribution (from 200 to 1700 nm). For assessment of the postharvest quality, cv. ‘Debora’ tomatoes, employed here as a model, were coated with CWN or CWM, at concentrations of 9 and 18%, and then compared to uncoated fruit during storage at 23 °C for 15 days. Evaluation of fruit quality, including sugar, acids, pH, water vapor loss, firmness, gloss, color, ethylene and respiratory activity, were assessed at every 3 days, while sensory test were carried out at the end of storage. Uncoated tomatoes presented the highest water loss values, meanwhile, firmness, ethylene, and respiratory activity were not largely modified by the coatings during storage. Tomatoes coated with the CWN exhibited the highest instrumental gloss and were preferred by consumers in sensory evaluations, indicating the potential of the as-developed carnauba wax green nanoemulsion for postharvest applications.

Quality Attributes of Refrigerated Barhi Dates Coated with Edible Chitosan Containing Natural Functional Ingredients.

Edible chitosan coatings with natural functional ingredients were used to preserve quality attributes of fresh Barhi date fruit. Fruits were coated with chitosan and/or 1 and 2% olive cake extract (OCE) or orange peel extract (OPE). Both coated and uncoated fruits were stored at 4 °C for 4 weeks. A slight decrease in the pH and increase in acidity with storage was observed. However, when chitosan was mixed with OCE or OPE, an increase in pH was observed with a concomitant decrease in acidity. The phenolic content of the samples was decreased with time. However, coating the date with OCE or OPE significantly (p ≤ 0.05) increased the total phenolic with a concomitant increase in radical scavenging activity. The textural properties, particularly hardness, were better preserved in case of coated dates. The sensory evaluation data showed non-significant changes in the acceptability of the Barhi dates throughout the storage period. Chitosan-coating significantly (p ≤ 0.05) inhibited mold growth over time. Scanning electron microscope (SEM) imaging showed difference among different coatings. According to principal component analysis (PCA), OCE and OPE were found to have protective effects on fruit quality.

Impact of Bacterial Cellulose Nanocrystals-Gelatin/Cinnamon Essential Oil Emulsion Coatings on the Quality Attributes of ‘Red Delicious’ Apples

This study aimed to assess the effectiveness of bacterial cellulose nanocrystals (BCNCs)-gelatin (GelA)/cinnamon essential oil (CEO) emulsion coatings containing various CEO concentrations (1200, 1800, and 2400 μL/L) in retarding ripening and senescence of ‘Red Delicious’ apples during cold storage (60 days at 4 °C). Coatings decreased the weight loss (WL) (~3.6%), as compared to uncoated fruit (~4.8%). A direct relationship between CEO concentration and respiration rate/ethylene production was also disclosed. Flesh firmness was higher for coated samples, with better results detected especially when the highest amount of CEO was applied (36.48 N for the 2400 μL/L delivered dose vs. 32.60 N for the 1200 μL/L one). These findings were corroborated by additional tests on the surface color, total acidity, soluble solids content, pH, ascorbic acid, and activities of polyphenol oxidase (PPO) and peroxidase (POD). This study demonstrated the capability of BCNCs-GelA/CEO systems to dramatically enhance the storability and quality of apples during refrigerated storage, thus avoiding undesired losses and increasing the economic performance of fresh fruit industries.

The use of bacteriophage-based edible coatings for the biocontrol of Salmonella in strawberries

The physicochemical quality and the effectiveness of antimicrobial activity against Salmonella and phage stability of dip-coated strawberries were investigated in this study by using bacteriophage cocktail with four different biopolymers for a period of 5 day at +4°Ϲ. The biopolymers used in this study were whey protein concentrate (WPC), carboxymethyl cellulose (CMC), chitosan (CH), and sodium alginate (SA). The phage cocktail was prepared using S. Enteritidis and S. Typhimurium obtained from the phages isolated from different environmental sources as host bacteria. Uncoated fruit was used as a control. The color, pH, and titratable acidity (TA) of strawberry samples and the stability and antimicrobial activity of bacteriophages during storage were also investigated. Amongst all the biopolymers, WPC coating showed the least escalation in pH and the least decrease in TA. During storage, 0.7 log-unit (PFU/g) reduction in WPC coating with the bacteriophage cocktail was observed. The highest antimicrobial effect was observed in WPC with a reduction of 3.1 log (CFU/g) after 5 days when the multiplicity of infection was 1000. In the light of the results, it was concluded that the phage loaded WPC coating had much better physicochemical and microbiological quality during refrigerated storage; therefore, it could be used effectively to extend the postharvest life of strawberries.

Fabrication and Characterization of Bio-Nanocomposites Based on Halloysite-Encapsulating Grapefruit Seed Oil in a Pectin Matrix as a Novel Bio-Coating for Strawberry Protection.

In the framework of designing a novel bio-coating for the preservation of fresh fruits, this paper reports the design, preparation, and characterization of novel bio-nanocomposites based on pectin loaded with grapefruit seed oil (GO), a natural compound with antimicrobial properties, encapsulated into halloysite nanotubes (HNTs). The vacuum-based methodology was used for the encapsulation of the oil into the hollow area of the nanotubes, obtaining nano-hybrids (HNT-GO) with oil concentrations equal to 20, 30, and 50 wt%. Physical properties (thermal, mechanical, barrier, optical) were analyzed. Thermal properties were not significantly (p < 0.05) affected by the filler, while an improvement in mechanical performance (increase in elastic modulus, stress at breaking, and deformation at breaking up to 200%, 48%, and 39%, respectively, compared to pure pectin film) and barrier properties (increase in water permeability up to 480% with respect to pure pectin film) was observed. A slight increase in opacity was detected without significantly compromising the transparency of the films. The release of linoleic acid, the main component of GO, was followed for 21 days and was correlated with the amount of the hybrid filler, demonstrating the possibility of tailoring the release kinetic of active molecules. In order to evaluate the effectiveness of the prepared bio-composites as an active coating, fresh strawberries were coated and compared to uncoated fruit. Qualitative results showed that the fabricated novel bio-coating efficiently extended the preservation of fresh fruit.

Assessing the Use of Aloe vera Gel Alone and in Combination with Lemongrass Essential Oil as a Coating Material for Strawberry Fruits: HPLC and EDX Analyses

Strawberry is a non-climacteric fruit but exhibits a limited postharvest life due to rapid softening and decay. A strawberry coating that is natural and safe for human consumption can be used to improve the appearance and safeguard the fruits. In this study, 20% and 40% Aloe vera gel alone or in combination with 1% lemongrass essential oil (EO) was used as an edible coating for strawberries. After application of all the treatments, the strawberry fruits were stored at a temperature of 5 ± 1 °C at a relative humidity (RH) of 90%–95% for up to 16 days and all the parameters were analyzed and compared to control (uncoated fruits). The results show that A. vera gel alone or with lemongrass EO reduced the deterioration and increased the shelf life of the fruit. Treatment with A. vera gel and lemongrass EO decreased acidity and total anthocyanins and maintained fruit firmness. Treatment with A. vera gel 40% + lemongrass EO 1% led to the lowest weight loss, retained firmness and acidity, but increased the total soluble solids and total anthocyanins compared to uncoated fruits during storage of up to 16 days. The phenolic compounds of A. vera gel were analyzed by HPLC, and the most abundant compounds were found to be caffeic (30.77 mg/mL), coumaric (22.4 mg/mL), syringic (15.12 mg/mL), sinapic (14.05 mg/mL), ferulic (8.22 mg/mL), and cinnamic acids (7.14 mg/mL). Lemongrass EO was analyzed by GC–MS, and the most abundant compounds were identified as α-citral (neral) (40.10%) ꞵ-citral (geranial) (30.71%), γ-dodecalactone (10.24%), isoneral (6.67%), neryl acetal (5.64%), and linalool (1.77%). When the fruits were treated with 20% or 40% A. vera gel along with 1% lemongrass, their total phenolic content was maintained during the storage period (from 4 to 8 days). The antioxidant activity was relatively stable during the 8 days of cold storage of the fruits coated with A. vera gel combined with lemongrass EO because the activity of both 20% and 40% gel was greater than that for the other treatments after 12 days of storage in both experiments. Moreover, all the treatments resulted in lower numbers of total microbes at the end of the storage period compared with the control treatment. This study indicates that the use of Aloe vera gel with lemongrass EO as an edible coating considerably enhances the productivity of strawberry fruits and the treatment could be used on a commercial scale.

Effect of Azadirachta indica and Tamarindus indica leaf extract and evaporative cooling on the quality characteristics and shelf life of sapota (Manilkara zapota)

Tropical fruits such as Sapota (Manilkara zapota) are highly perishable. The main reasons for the quality deterioration of these fruits are field heat and microbial attack, which can be reduced by proper cooling techniques and by using antimicrobial agents. The present study was undertaken to extend the shelf life of Sapota using evaporative cooling and antimicrobial coating, namely, neem leaves (Azadirachta indica) and tamarind leaves (Tamarindus indica), at different concentrations (20, 50 and 100%). Coated Sapota fruits were stored for 24 days, whereas uncoated fruits were stored for only 7 days. Both the selected antimicrobial extracts showed antimicrobial activity, and the cooling efficiency of the evaporative cooling chamber was 81-85%. Fruits were cooled to 15-18°C (core temperature), which could enable retention of physio-chemical properties. The results indicated that fruits coated with the highest level (100%) of antimicrobial extract coating (neem leaves and tamarind leaves) and stored under evaporative cooling conditions had the lowest percentage loss in weight (5-7% after 24 days of storage) and good retention of total soluble solids (1-2%), pH (2-3%) and total sugars (3-5%). Thus, coating Sapota fruits with neem leaves and tamarind leaf extracts and storing them under evaporative cooling conditions can be a better way to enhance the shelf life of sapota.

Amla essential oil‐based nano‐coatings of Amla fruit: Analysis of morphological, physiochemical, enzymatic parameters, and shelf‐life extension

This study aimed to develop and examine the potential effect of Amla essential oil-based nano-coatings at different concentrations 0.0, 2.5, 5.0, 7.5, and 10.0% (v/v) on Amla fruits stored in the room conditions (29 ± 2°C and 45%RH) for 15 days. Nanoemulsions were formulated by ultrasonication with Amla essential oil along with modified corn starch (2% w/v) and Tween 80 (5% v/v). All the shelf-life parameters were analyzed at an interval of 3 days. Results have shown that nano-coatings have a positive and significant effect on delaying browning and total yeast and mold count. Fruits having nano-coatings effectively retained their antioxidant activity along with bioactive components in comparison with the uncoated fruits. Particle size, Zeta potential, and polydispersity index of the best-performed nano-coating having 10% (v/v) of Amla essential oil were also evaluated. Thus, our findings suggest that Amla essential oil-based nano-coatings had a promising effect on enhancing the shelf life of Amla fruits. Novelty impact statement The fruits coated with nanoemulsions maintained good fruit quality with a lower decay percentage, the least degradation of ascorbic acid and chlorophyll, and high retention of antioxidant activity and bioactive compounds. The application of Amla essential oil-based nano-coatings had a promising effect on fungal decay, weight loss, firmness, browning index, and other color attributes of fruits. Amla essential oil-based nano-coatings had a promising effect on enhancing the shelf life of Amla fruits.

Development of gelatin-carboxymethylcellulose coatings incorporated with avocado epicarp and coconut endocarp extracts to control fungal growth in strawberries for shelf-life extension

ABSTRACT The objective of this study was to incorporate avocado peel (AEE) and coconut (CEE) extracts as antifungal additive in the development of gelatin and carboxymethylcellulose coatings to extend shelf life in strawberries. Fractions of 200 mg/L of extracts were incorporated in the coating and characterized during storage at 2°C. AEE and CEE in the coating delayed significantly (P < .05) weight loss (40%), softening, color, and compositional changes (°Brix, sugars, titratable acidity). Rhizopus stolonifer and Aspergillus niger strains were isolated and inoculated to evaluate the effectiveness of the coatings on strawberries. The use of the coating + plant extracts decreased the proliferation of fungi by 45% compared to the uncoated fruit and extended the shelf life for 15 days. With these findings, it is suggested that biopolymeric coatings + plant extracts can be used as a potential method of ecological preservation in strawberries against microbial deterioration.

Non-radical synthesis of chitosan-quercetin polysaccharide: Properties, bioactivity and applications

Quercetin-chitosan (QCS) polysaccharide was synthesized via non-radical reaction using L-valine-quercetin as the precursor. QCS was systematically characterized and demonstrated amphiphilic properties with self-assembling ability. In-vitro activity studies confirmed that quercetin grafting does not diminish but rather increases antimicrobial activity of the original chitosan (CS) and provided the modified polysaccharide with antioxidative properties. QCS applied as a coating on fresh-cut fruit reduced microbial spoilage and oxidative browning of coated melon and apple, respectively. Notably, QCS-based coatings prevented moisture loss, a major problem with fresh produce (2%, 12% and 18% moisture loss for the QCS-coated, CS-coated and uncoated fruit, respectively).The prepared QCS polysaccharide provides advanced bioactivity and does not involve radical reactions during its synthesis, therefore, it has good potential for use as a nature-sourced biocompatible active material for foods and other safety-sensitive applications.

Biochemical content of cherry laurel (Prunus laurocerasus L.) fruits with edible coatings based on caseinat, Semperfresh and lecithin

Cherry laurel is one of the most important cherry species and naturally grown in Black sea region in Turkey. Its fruits are sold at high price in local markets in northern parts of Turkey. Cherry laurel fruits are very perishable with a limited shelf life due to a high metabolic activity and susceptibility to mechanical damage and microbial attack. The effect of edible coatings (EC) based on caseinat, Semperfresh and lecithin on the fruit quality, bioactive content and antioxidant activity of cherry laurel fruits stored at 4 ± 1 °C for 15 days was evaluated. The EC fruits compared with uncoated fruits in terms of weight loss, brix, color, pH, titratable acidity, reducing sugar, total sugar, sucrose, total phenolic content, DPPH-IC50, ABTS-IC50, total yeast-mold count, number of total mesophilic aerobic bacteria and ascorbic acid (Vitamin C). Results showed that Semperfresh coating was more promising on titratable acidity (0.26%), pH (4.63), invert sugar (11.77 g/100 g), total sugar (11.96 g/100 g) and sucrose (0.13 g/100 g), caseinat coating was found more promising for count of total yeast-mold count (2.93 log kob/g) and total mesophilic aerobic bacteria (3.44 log kob/g) and lecithin coating was more promising in terms of weight loss (6.77%). For radical scavenging activity and total phenolic content, Semperfresh was found more useful. Thus, caseinat, Semperfresh and lecithin showed to be a promising alternative in prolonging shelf life and preserving the quality of cherry laurel.

EFFECT OF PROPIONIC ACID AND MIXED WAX (BEE-CARNAUBA WAX) ON TOTAL MICROORGANISM AND QUALITY OF PURPLE PASSION FRUIT AT AMBIENT TEMPERATURE

The effects of propionic acid and mixed wax (bees and carnauba wax; MW) on total microorganisms and quality of purple passion fruit at ambient temperature 25±2°C and 70%–80% relative humidity were studied. The fruits were dipped in propionic acid solution at the concentrations of 0.15%; 0.25%; 0.35% (v/v) and 0.2% carbendazim, then coated with MW 2.5% by hand. After drying, they were stored at 25 ± 2 °C for 18 days. Uncoated fruits were preserved at the same temperature as control. The determination parameters were isolation and identification of microorganisms, total microorganism, percentage of fruit decay, weight loss, total soluble solids content (TSS), total sugars, titratable acidity, and ascorbic acid content; interval time was every 3 days of storage time. The results showed that identified two kinds of microorganism were Fusarium moniliforme var. subglutinans and Fusarium oxysporum Schlecht. The concentration of 0.25% propionic acid solution and MW coating could reduce the percentage of weight loss, fruit decay, and total microorganisms for 18 days of storage time. Moreover, this combination could remain chemical qualities, as TSS, total sugars, titratable acidity, ascorbic acid content in 18 days of storage time.

The effect of layer-by-layer edible coating on the shelf life and transcriptome of ‘Kosui’ Japanese pear fruit

Edible coatings attract much interest today as safe and effective techniques for maintaining quality and extending shelf life of fruit and vegetables. However, the underlying molecular mechanisms remain unclear. The aim of this study was to identify genes involved in enhancement of shelf life in ‘Kosui’ Japanese pear (Pyrus pyrifolia Nakai) fruit by chitosan/alginate-based layer-by-layer (LBL) edible coatings. Both tri-layer and penta-layer LBL coatings effectively minimized fruit respiration and ethylene production rates, inhibited flesh firmness loss, and prevented peel color change for 21 d at 20 °C but had little effect on weight loss. Gas permeability tests on polyethylene terephthalate films revealed that LBL coatings substantially lowered oxygen transmission rates but had little effect on water vapor transmission rate. In an attempt to identify the pathways involved, we monitored gene expression in LBL-coated and uncoated fruit by RNA-Seq analysis. This analysis revealed a clear downregulation of genes associated with ethylene production and fruit ripening, as well as the tricarboxylic acid cycle following application of LBL edible coating. On the other hand, genes associated with the glycolysis pathway were mostly upregulated. Together, these results indicate that prolonged shelf life by chitosan/alginate-based LBL edible coating could primarily result from control of the balance of aerobic-anaerobic metabolism.

Postharvest quality of strawberry (Fragaria × ananassa duch.) coated with calcium and nano-chitosan as affected by different storage temperatures

Purpose: The aim of the study was to identify the impacts of storage temperature on strawberries coated with 3% calcium chloride (CaCl2) and 0.2% nano-chitosan. Research method: Fresh strawberry fruit were immersed in CaCl2 solution of 3% for 1 min and drained at room temperature before coating with nano chitosan solution of 0.2 %. The treated fruit was then stored at 0 oC, 2 oC, 4 oC and 25 °C. Physico-chemical analysis was performed in each three-day interval. Findings: Of the four examined temperatures tested, storing the fruit at 0 oC was the most effective in maintaining the overall quality index of strawberries up to 21 days. The treatment also reduced weight loss, preserved ascorbic acid content, antioxidant capacity, and total anthocyanin content, prevented microbial growth and prolonged storage-life of treated strawberries up to 21 days. Limitations: the industrial packaging that could affect the actual influences of the studied temperatures was not investigated in this work. Originality/Value: storing fresh strawberries coated with CaCl2 3%, nano-chitosan 0.2% at 0 oC was the most effective treatment in lengthening the shelf life of the fruit up to 21 days. The combination treatment of coating and storing at 2 oC extents strawberry storage life by 6 days when compared to uncoated fruit.

Magnetization Improved Fine Particle Biochar Adsorption of Lead

ABSTRACT Biochar can be an alternative sorbent to the high cost activated carbon for wastewater treatment. Its adsorption capacity for heavy metals can be increased by magnetizing it with iron. In this study, we compared the physiochemical properties and sorption capacity of an iron-coated fine empty fruit bunch biochar (IC-EFBB) for Pb with a commercially available activated carbon (AC) and the uncoated fine empty fruit bunch biochar (EFBB). The results revealed that the AC had greater micropores surface area (671.14 m2 g−1), compared to the IC-EFBB (25.79 m2 g−1) and EFBB (2.57 m2 g−1). On the other hand, the IC-EFBB had the highest pH, and content of functional groups (OH and CO) while the EFBB had the highest total oxygen containing functional groups, CEC, and the lowest PZC. The sorption data of Pb by EFBB, IC-EFBB and AC were better fitted to the Langmuir adsorption as indicated by the R2 (1.00, 1.00 and 0.98, respectively) and RMSE values (0.009, 0.017 and 0.428, respectively). The IC-EFBB (142.86 mg g−1) had the highest adsorption capacity for Pb followed by EFBB (103.09 mg g−1) and the lowest was AC (50.51 mg g−1). The results indicated that surface area was not an important indicator for Pb sorption by the adsorbents but the amount of oxygen-containing functional groups, pH and CEC were the dominant factors. The IC-EFBB was readily separated from the aqueous solution using an external magnetic force. Therefore, it can be concluded that the IC-EFBB can be a very good alternative sorbent to remove heavy metals from wastewater.