Fruit Color Changes Research Articles

Regulation of Anthocyanin Accumulation by a Transcription Factor LcTT8 From Lonicera caerulea L.

The fruit of Lonicera caerulea L. is rich in anthocyanin, which has beneficial effects on human health. However, there is no research report on the regulation mechanism of anthocyanin synthesis in Lonicera caerulea L. TT8 gene-encoded protein belongs to bHLH transcription factor, and it has been reported to regulate anthocyanin synthesis. In the study, we cloned TT8 gene from Lonicera caerulea L. named “Berel” and transformed into tobacco (Nicotiana tabacum) to characterize its function. The open-reading frame of LcTT8 was 2049 bp, encoding a protein of 682 amino acids. The phylogenetic tree analysis showed that LcTT8 protein had the highest homology with TT8 in Paeonia suffruticosa. The analysis of expression in different tissues showed that the expression level of LcTT8 was higher in fruits than that in flowers, leaves, stems, and roots, and the expression level reached the peak at the early stage of fruit color change. The subcellular localization results showed that the LcTT8 protein was mainly localized in the nucleus. A total of ten LcTT8 overexpression transgenic tobacco were obtained. The ELISA results revealed that the anthocyanin content in the transgenic tobacco leaves was increased by 36.84% compared with the wild-type tobacco. The qPCR results showed that the overexpression of LcTT8 caused the up-expression of key genes of anthocyanin synthesis, including F3H, DFR, and ANS. Similarly, the enzyme activities of DFR and ANS were significantly increased in the transgenic lines (P < 0.05). Our research reveals the expression patterns and molecular characteristic of LcTT8 gene in anthocyanin synthesis, providing new possibilities for the breeding of blue honeysuckle and other fruit plants with high anthocyanin accumulation.

Effects of Different Drying Methods and Temperature on the Drying Behavior and Quality Attributes of Cherry Laurel Fruit

This study aimed to investigate the effect of different drying methods and drying temperature on the drying kinetics, total bioactive compounds, phenolic profile, microstructural properties, rehydration kinetics, and color change of cherry laurel fruit. For this aim, hot air drying (HAD), ultrasound-assisted vacuum drying (USV), and freeze-drying (FD) were conducted on drying of cherry laurel. HAD and USV were conducted at 50, 60, and 70 °C. Drying times of the samples were 1980, 1220, and 770 min for HAD at 50, 60 and 70 °C, and 950, 615, and 445 min at 50, 60, and 70 °C, respectively, for USV. The total bioactive compound was significantly affected by both drying methods and temperature (p &lt; 0.05). FD exhibited the highest total phenolic (TPC), total flavonoid (TFC), total anthocyanin (TAC), and antioxidant capacity value USV showed a higher amount of bioactive compounds than those of HAD at the same drying temperature. The content of total bioactive compounds significantly increased as the temperature increased for both HAD and USV (p &lt; 0.05). The chlorogenic acid was identified as a major phenolic, and its amount significantly depended on drying methods (p &lt; 0.05). SEM images described the surface characteristic of dried samples. HAD dried products showed higher shrinkage compared to FD and USV. All drying methods significantly affected the total color difference (ΔE) values (p &lt; 0.05). This study proposed that USV could be as an alternative method to HAD due to higher bioactive compounds retention and rehydration ratio, shorter drying time, less color change, and shrinkage formation.

Determination of Pear Cultivars (Pyrus communis L.) Based on Colour Change Levels by Using Data Mining

Colour is an essential parameter at product quality control stages, and finally, it is necessary for the consumer marketing decision. It is possible to damage the products during the process from collection to storage. Also, it is a well-known condition, cold environmental conditions protect fruits from deformations negative effects, but most of the time, most of the consumers keep the fruits at room temperature in open packs during the consumption process. Also, this condition affects the product storage time. In this study, it is aimed that to determine the behaviours of the fruits in room temperature and humidity conditions. For this aim the colour change of the damaged pears were determined, in another term, colour change value from red to green and yellow to blue at the damaged pears were determined with lightness values by using image analysis technique and analysed with data mining methods. For this purpose, 100 “Akça” pear and 100 “Deveci” local pear cultivar used for experiments. Fruits were equally damaged by using a pendulum mechanism. The damaged fruits were kept at room temperature. Colour change areas on fruits were evaluated with X-rite Ci60 spectrophotometer, and the hardness of fruits was measured by using a fruit penetrometer. The colour (L, a, b) and ΔE values were analysed for the fruit cultivars. The relationship between fruit hardness and colour change were also demonstrated. The predictions were done supervised machine learning algorithms (Decision Tree and Neural Networks with Meta-Learning Techniques; Majority Voting and Random Forest) by using KNIME Analytics software. The classifier performance (accuracy, error, F-Measure, Cohen's Kappa, recall, precision, true positive (TP), false positive (FP), true negative (TN), false negative (FN) values were given at the conclusion section of the research. The best prediction were found at the Majority Voting method (MAVL) 98.458 % success given with 70% partitioning.

Application of hue spectra fingerprinting during cold storage and shelf-life of packaged sweet cherry

Presented work investigated the application of a new color analysis technique in post-harvest life of sweet cherry (Prunus avium L. ‘Hudson’). The hue spectra fingerprinting creates a histogram of image colors by summarizing the saturation. The advantage of this calculation method is that vivid colors make peaks while neutral background color is eliminated without object segmentation. Partial Least Squares (PLS) regression was used to estimate reference parameters during 9 d cold storage at 10 ± 0.5 °C (RH = 90 ± 1%) and following 2 d shelf-life at 20 ± 0.5 °C. The reference parameters of respiration, weight loss, fruit firmness and total soluble solid (TSS) content were measured. Samples were split into seven groups according to the number of perforations of polypropylene film and fructose concentration of moisture absorber. It was observed that parameters TSS and fruit firmness were the most sensitive to the length of storage. Weight loss was affected significantly by packaging. All reference parameters were estimated by PLS model with R2 > 0.917, but weight loss and respiration obtained high estimation error of RMSE% = 48.02% and 11.76%, respectively. TSS and fruit firmness prediction were successful with RMSE% = 0.84% and 1.85%, respectively. Desiccation and color change of peduncle became visible in the green range of hue spectra. Color change of red fruit was observed with decreasing saturation in the red range of hue spectra. Our findings suggest that hue spectra fingerprinting can be a useful nondestructive method for monitoring quality change of sweet cherry during post-harvest handling and shelf-life.

Determination of rainfall effects on kaolin clay coverage rates used in prevention plant from sunburn

Sunburn, which is an important problem in agricultural products grown in arid and semi-arid regions, causes economic losses of up to 40-60% in some years. Sunburn occurs as a result of overheating of the surfaces of fruits exposed to high air temperature and solar radiation from the sun. Increase in the temperature stress for plants is observed during months of high temperature, this is one of the main reasons for many negative conditions (changes in fruit colour, cell death in plants, etc.) in fruits and leaves. While the shelf life of damaged agricultural products is shortened, deterioration is observed even in the storage stage. Today, different applications are made to reduce the sunburn in many kinds of fruits and sunburn damage can be significantly reduced as a result of these applications. For this purpose, it was aimed to reduce the temperature on the leaf surface by the application of kaolin clay (Trade name; Güneş Stop) applied to the plant surface at the beginning of the season. In the study; eight different concentrations of kaolin clay with tree application volume were applied and after the application, leaf samples of the citrus trees were taken from the predetermined regions, and the coverage rate was measured in an image processing program. From 8 different regions, 15 pieces of leaf were randomly taken from each region. The same process was carried out again by collecting leaf samples from the same regions after the rain; thus, the performance analysis of kaolin clay was determined after the rainfall. As a result of kaolin clay application; according to the results of image analysis of average leaf surface coverage rates obtained by regions and after the rainfall, the results obtained from the same regions showed that kaolin clay was washed at a rate of 39.64% with precipitation.

Hydrogen Sulfide Maintained the Good Appearance and Nutrition in Post-harvest Tomato Fruits by Antagonizing the Effect of Ethylene.

Hydrogen sulfide (H2S) could act as a versatile signaling molecule in delaying fruit ripening and senescence. Ethylene (C2H4) also plays a key role in climacteric fruit ripening, but little attention has been given to its interaction with H2S in modulating fruit ripening and senescence. To study the role of H2S treatment on the fruit quality and nutrient metabolism, tomato fruits at white mature stage were treated with ethylene and ethylene plus H2S. By comparing to C2H4 treatment, we found that additional H2S significantly delayed the color change of tomato fruit, and maintained higher chlorophyll and lower flavonoids during storage. Moreover, H2S could inhibit the activity of protease, maintained higher levels of nutritional-related metabolites, such as anthocyanin, starch, soluble protein, ascorbic acid by comparing to C2H4 treatment. Gene expression analysis showed that additional H2S attenuated the expression of beta-amylase encoding gene BAM3, UDP-glycosyltransferase encoding genes, ethylene-responsive transcription factor ERF003 and DOF22. Furthermore, principal component analysis suggested that starch, titratable acids, and ascorbic acid were important factors for affecting the tomato storage quality, and the correlation analysis further showed that H2S affected pigments metabolism and the transformation of macromolecular to small molecular metabolites. These results showed that additional H2S could maintain the better appearance and nutritional quality than C2H4 treatment alone, and prolong the storage period of post-harvest tomato fruits.

Comparative Study on Biological Characteristics and Fruit Quality Changes of Two Citrus Varieties

This experiment compared the phenophase, morphological features and fruit quality of the two citrus varieties. The results showed that the whole growth period of Lemon Siranui was about 12 days longer than Siranui. The flowering period, two physiological fruit drop periods and fruit color change period of Lemon Siranui were about 5-7 days later than Siranui. While this study illustrated differences in morphological features that Lemon Siranui tree was stronger than Siranui. And the fruit of Lemon Siranui was heavier than Siranui. It was clear to see that the percentages of soluble solids as well as vitamin C in Lemon Siranui were larger than those in Siranui, which led to better taste qualities. Overall, Lemon Siranui was a new high-quality strain citrus variety with excellent traits which was worth promoting from the analysis of appearance quality and nutritional quality.

Effect of different drying methods on total bioactive compounds, phenolic profile, in vitro bioaccessibility of phenolic and HMF formation of persimmon

This study aims to investigate the effects of different drying methods namely, ultrasound-assisted vacuum-drying (USV), freeze-drying (FD), infrared-drying (ID) and hot-air drying (HAD) on bioactive compounds, phenolic profile, in vitro bioaccessibility of phenolic compounds, color change, sugar profile and HMF formation of persimmon fruits. Total phenolic contents (TPC) were 77.2, 112.5, 124.9 and 262.4 mg GAE/100 g for HAD, ID, USV, and FD, respectively. CUPRAC, DPPH, β-carotene and lycopene level were 219.2–635.2 mg TE/100 g, 101.1–299.7 mg TE/100 g, 294.3–438.5 mg/100 g and 720.6–966.5 mg/100 g, respectively. Drying methods significantly affected both amounts of individual phenolics and their distribution (P < 0.05). Epigallocatechin was determined as a major phenolic compound for all samples (88.2–383.2 mg/100 g). All drying process significantly increased the bioaccessibility of phenolic compounds (P < 0.05). HAD showed the highest in vitro bioaccessibility. All drying methods significantly affected ΔE values (P < 0.05). HMF values were 12.1, 15.0 and 23.4 mg/kg for ID, USV and HAD samples, respectively and was not found for FD. This study suggested that USV and ID could be used as an alternative drying method to FD and conventional drying due to high drying rate, less phenolic degradation, HMF formation, and color change.

Fine Mapping of Lycopene Content and Flesh Color Related Gene and Development of Molecular Marker-Assisted Selection for Flesh Color in Watermelon (Citrullus lanatus).

Lycopene content and flesh color are important traits determined by a network of carotenoid metabolic pathways in watermelon. Based on our previous study of genetic inheritance and initial mapping using F2 populations of LSW-177 (red flesh) × cream of Saskatchewan (pale yellow flesh), red flesh color was controlled by one recessive gene regulating red and pale yellow pigmentation, and a candidate region related to lycopene content was detected spanning a 392,077-bp region on chromosome 4. To obtain a more precise result for further study, three genetic populations and a natural panel of 81 watermelon accessions with different flesh colors were used in this research. Herein, we narrowed the preliminary mapping region to 41,233 bp with the linkage map generated from F2 populations of LSW-177 (red flesh) × cream of Saskatchewan (pale yellow flesh) with 1,202 individuals. Two candidate genes, Cla005011 and Cla005012, were found in the fine mapping region; therein Cla005011 was a key locus annotated as a lycopene β-cyclase gene. Phylogenetic tree analysis showed that Cla005011 was the closest relative gene in gourd. LSW-177 × PI 186490 (white flesh) and another BC1 population derived from garden female (red flesh) × PI 186490 were generated to verify the accuracy of the red flesh candidate gene region. By analyzing the expression levels of candidate genes in different developmental stages of different color watermelon varieties, Cla005011 for the expression differences was not the main reason for the flesh color variation between COS and LSW-177. This indicated that the LCYB gene might regulate fruit color changes at the protein level. A new marker-assisted selection system to identify red and yellow flesh colors in watermelon was developed with flesh color–specific CAPS markers and tested in 81 watermelon accessions.

An integrated metabolomic and gene expression analysis identifies heat and calcium metabolic networks underlying postharvest sweet cherry fruit senescence.

Ηeat and calcium treatments reprogram sweet cherry fruit metabolism during postharvest senescence as evidenced by changes in respiration, amino acid metabolism, sugars, and secondary metabolites shift. Heat and calcium treatments are used to improvepostharvest fruit longevity; however, the exact mechanism remains poorly understood. To characterize the impact of these treatments on sweet cherries metabolism, 'Lapins' fruits were treated with heat or CaCl2 solutions and their combination and subsequently were exposed at room temperature, for up to 4days, defined as senescence period. Single and combined heat and calcium treatments partially delayed fruit senescence, as evidenced by changes in fruit colour darkening, skin penetration force, and respiration activity. Calcium content was noticeably increased by heat in Ca-treated fruit. Several primary metabolites, including amino acids, organic acids, and alcohols, were decreased in response to both treatments, while many soluble sugars and secondary metabolites were increased within 1day post-treatment.Changes of several metabolites in heat-treated fruits, especially esculetin, peonidin 3-O-glucoside and peonidin 3-O-galactoside, ribose, pyroglutamate, and isorhamnetin-3-O-rutinoside, were detected. The metabolome of fruit exposed to calcium also displayed substantial modulations, particularly in the levels of galactose, glycerate, aspartate, tryptophan, phospharate rutin, and peonidin 3-O-glucoside. The expression of several genes involved in TCA cycle (MDH1, IDH1, OGDH, SUCLA2, and SDH1-1), pectin degradation (ADPG1) as well as secondary (SK1, 4CL1, HCT, and BAN), amino acids (ALDH18A1, ALDH4A1, GS, GAD, GOT2, OPLAH, HSDH, and SDS), and sugar (PDHA1 and DLAT) metabolism were affected by both treatments. Pathway-specific analysis further revealed the regulation of fruit metabolic programming by heat and calcium. This work provides a comprehensive understanding of metabolic regulation in response to heat and calcium during fruit senescence.

Climatic influences on fruit quality and sensory traits of cactus pear (Opuntia ficus-indica): a 5-year evaluation

Cactus pears were introduced into South Africa and are used mainly as fodder crops. Interest in commercial fruit production has increased in the past few years. Since Opuntia ficus-indica and Opuntia robusta flourish in arid and semi-arid regions, it is worth looking into their potential not only as a fodder crop in dry seasons, but also for fruit production. Forty-two cultivars are being evaluated at an experimental orchard at Bloemfontein in the Free State Province in South Africa. Twelve cultivars with commercial fruit production potential were selected for evaluation of fruit eating quality as well as the effect of climate thereon. These were evaluated over five production seasons. Correlations were drawn on the influence of maximum temperature, heat units and rainfall on fruit quality. Rainfall had a significant positive effect on fruit mass, total soluble solids (TSS) content, glucose content, pulp pH and percentage titratable acidity (% TA), while it had a negative effect on percentage pulp and betacyanin (Bc) and betaxanthin (Bx) pigment contents. Fruit mass, TSS, glucose, fructose content and % TA correlated negatively with total heat units, while % pulp, vitamin C content, pulp pH, Bc and Bx correlated positively with total heat units. Maximum temperatures had similar effects on fruit quality to those observed for heat units, except for pulp pH. From these data, it is clear that all climatic factors measured correlated to changes in fruit quality, especially TSS, sugars, acidity and colour (pigments), although the effect of rainfall was most profound.

Evaluating the efficacy of chitosan and CMC incorporated with moringa leaf extracts on reducing peteca spot incidence on 'Eureka' lemon.

Lemon (Citrus limon L.) is one of the most cultivated citrus fruit in South Africa. In citrus packhouses, fruit are coated with commercial synthetic waxes to enhance shelflife. However, the use of waxes has been linked to peteca spot (PS) incidence in lemons. This study evaluated the efficacy of chitosan (CH) and carboxymethyl cellulose (CMC) incorporated with moringa leaf extracts (M) on reducing peteca spot incidence on 'Eureka' lemon. A total of 500 'Eureka' lemons were harvested from outside and inside canopy positions from a commercial orchard in KwaZulu-Natal, South Africa. Fruit were assigned to five coating treatments, namely; control, 1% M + CMC, 1% CMC, 1% CH and 1% M + CH. After coating, fruit were transferred into a cold room with delivery air temperature set at 3°C for 12weeks to induce the disorder. At each sampling week, peteca spot incidence, fruit physicochemical and phytochemical properties including color, mass, vitamin C, carotenoids, TSS, TA and phenolics were measured. The results showed that coating treatments and canopy position significantly affected PS incidence. Fruit coated with M + CMC, CMC, CH were less susceptible to PS development in both inside and outside canopy compared to the control and M + CH coated fruit. Coating treatments significantly affected phenolic and flavonoid concentration. Moreover, coating treatments significantly reduced mass loss, ascorbic acid loss and delayed color change of fruit. The results found in this study demonstrated the ability of either M + CMC, CMC, or CH as coating treatments for reducing PS in 'Eureka' lemon.

Changes of peel color and fruit quality in navel orange fruits under different storage methods

Fruit color is one important traits that largely determine the quality of navel orange fruits. The goal of this work was to evaluate the influence of ventilating warehouse (VW), mechanical refrigeration warehouse (MRW) and mountain evaporative cooling ventilating warehouse (MECW) storage on the quality and peel color in navel orange. The weight loss rate, decay rate, total soluble solids (TSS), titratable acidity (TA) and vitamin C (Vc) content of fruit were measured. The color index of the skin was determined by a chromameter, and the carotenoids from the skin were determined by high performance liquid chromatography. During storage, the weight loss rate and rot rate of navel orange fruit gradually increased, and TSS, TA and Vc gradually degraded. The weight loss rate and decay rate of fruits stored in MRW and MECW were lower than those of fruits stored in VW, and the contents of TSS, TA and VC were higher than those of fruits stored in VW. However, the color change of VW and MECW fruits was better than that of MRW fruits. The chlorophyll content of VW and MECW fruits was significantly lower than that of MRW fruits, and the carotenoid content of VW and MECW fruits was significantly higher than that of MRW fruits in the late storage period. Our study suggests that MECW had the best storage effect among the three storage methods, which provided a theoretical basis for the practical application of MECW in citrus fruit storage.

Comparative transcriptome analysis uncovers the regulatory functions of long noncoding RNAs in fruit development and color changes of Fragaria pentaphylla

To investigate the molecular mechanism underlying fruit development and color change, comparative transcriptome analysis was employed to generate transcriptome profiles of two typical wild varieties of Fragaria pentaphylla at three fruit developmental stages (green fruit stage, turning stage, and ripe fruit stage). We identified 25,699 long noncoding RNAs (lncRNAs) derived from 25,107 loci in the F. pentaphylla fruit transcriptome, which showed distinct stage- and genotype-specific expression patterns. Time course analysis detected a large number of differentially expressed protein-coding genes and lncRNAs associated with fruit development and ripening in both of the F. pentaphylla varieties. The target genes downregulated in the late stages were enriched in terms of photosynthesis and cell wall organization or biogenesis, suggesting that lncRNAs may act as negative regulators to suppress photosynthesis and cell wall organization or biogenesis during fruit development and ripening of F. pentaphylla. Pairwise comparisons of two varieties at three developmental stages identified 365 differentially expressed lncRNAs in total. Functional annotation of target genes suggested that lncRNAs in F. pentaphylla may play roles in fruit color formation by regulating the expression of structural genes or regulatory factors. Construction of the regulatory network further revealed that the low expression of Fra a and CHS may be the main cause of colorless fruit in F. pentaphylla.

Putrescine treatment reduces yellowing during senescence of broccoli (Brassica oleracea L. var. italica)

Broccoli undergoes yellowing very quickly in storage, which impacts its’ quality and economic value. The current study examined the ability of putrescine to inhibit postharvest yellowing of broccoli florets. Broccoli heads were dipped in a 0.25 mmol L−1 solution of putrescine for 10 min, air dried, and then stored at 20 °C in the dark. Results indicated that, relative to the untreated control, putrescine treatment effectively suppressed changes in fruit color from green to yellow, reduced the degradation of chlorophyll, decreased electrolyte leakage, inhibited the accumulation of malondialdehyde, and maintained the enzyme activity and gene expression of peroxidase, catalase, and ascorbate peroxidase. The relative expression of chlorophyllase Ⅰ (BoCLH1) and chlorophyllase Ⅲ (BoCLH3) was enhanced while the relative expression of chlorophyllase Ⅱ (BoCLH2), pheophorbide a oxygenase (BoPAO), and pheophytinase (BoPPH) was reduced by putrescine. The data clearly indicate that putrescine reduces the yellowing of broccoli florets and may represent an effective approach for reducing postharvest losses in broccoli.

Evaluation of different ripening inducers on the quality, proximate composition and mineral residue in plantain (MusaAAB) fruits

The indiscriminate use of ripening inducers to ripen fruits for domestic markets threatens food safety. Consequently, there is a need to determine the efficacy of inducers used in the industry. Four ripening inducers from plant sources namely; yellow pawpaw leaf, apple, avocado and African bush mango fruits were used to ripen plantain fruits stored in perforated wooden boxes (28-29°C and 77-78% RH). Their effects were compared with those ripened with ethylene glycol or those without ripening inducers (control). The treatment was applied following a completely randomized design replicated four times. Data were collected on fruit colour change, firmness, physiological fresh weight loss, total soluble solids (TSS), total titratable acidity, proximate contents, vitamins A and C and mineral deposit on the ripened plantain fruits. Plantain fruits attained full ripe state on the 4th day when induced with yellow pawpaw leaf, ethylene glycol, avocado and apple fruits compared to 9 days in the control. Ripening with yellow pawpaw leaves significantly (p<0.05) enhanced vitamin C, TSS, crude protein, fat and fiber contents in plantain fruits at full ripe stage (40.54 mg 100 g(-1), 8.70%, 3.51 g 100 g(-1), 1.67 g 100 g-1, 6.26 g 100 g(-1), respectively) while least values for these parameters were recorded in plantain ripened with ethylene glycol (38.75 mg 100 g(-1), 7.96%, 3.11 g 100 g(-1), 1.42 g 100 g(-1), 5.43 g 100 g(-1), respectively). Significant residues of heavy metal residue (cadmium - 0.01 µg 100 g(-1), chromium - 0.04 µg 100 g(-1), mercury - 0.13 µg 100 g(-1)) were observed in ethylene glycol ripened plantain fruits, while none was observed in fruits ripened with plant materials and control. Yellow pawpaw leaves could serve as cost-effective and safe ripeners for plantain fruits.

Effects of Chitosan-Based Coatings Enriched with Cinnamaldehyde on Mandarin Fruit cv. Ponkan during Room-Temperature Storage

The current work aimed to evaluate the efficacy of four coating formulations—chitosan coating (CH), 0.5% cinnamaldehyde + chitosan (0.5% CI–CH), 1.0% cinnamaldehyde + chitosan (1.0% CI–CH), and 1.5% cinnamaldehyde + chitosan (1.5% CI–CH)—on fresh mandarin fruit cv. Ponkan quality maintenance (weight loss, decay rate, total soluble solids, titratable acidity, vitamin C, color index, malondialdehyde, and antioxidant activity) over 100 days of storage at 20 °C. Compared to the control, chitosan treatment effectively reduced the decay and weight loss rates of mandarin fruit cv. Ponkan during storage at room temperature, delayed the decline of nutritional quality in fruits, increased the antioxidant capacity, and inhibited the accumulation of malondialdehyde (MDA). In comparison to chitosan coating, 1.5% CI–CH did not improve the fruit storage effect, but inhibited the normal color change of fruits and increased the accumulation of MDA. Both 0.5% CI–CH and 1.0% CI–CH effectively reduced the rate of fruit decay, improved the quality of fruits after harvest, and delayed fruit aging. Our study suggests that 0.5% CI–CH and 1.0% CI–CH might be good formulations for maintaining the quality of mandarin fruit cv. Ponkan during room-temperature storage.

A starch edible surface coating delays banana fruit ripening

A rice starch edible coating blended with sucrose esters was developed for controlling the postharvest physiological activity of Cavendish banana to extend postharvest quality during ripening at 20 ± 2 °C. Coating effectiveness was assessed against changes in fruit physiochemical parameters such as weight loss, titratable acidity, total soluble solids, flesh fruit firmness, ion leakage, colour change, respiration, ethylene production, chlorophyll degradation and starch conversion were determined. The topography of coating material on the fruit surface was evaluated by scanning electron microscope (SEM). Surface morphology studies highlighted the binding compatibility of the coating matrix with the fruit peel character and formed a continuous uniform layer over the fruit surface. The results showed that the coating was effective in delaying ethylene biosynthesis and reducing respiration rate. Other factors impacting included delayed chlorophyll degradation, reduced weight loss and retention of fruit firmness for the first six days, all of which improved the commercial value of the fruit. The shelf life of coated fruit was prolonged for 12 days in comparison with the untreated control which ripened within seven days and lost marketability after Day 6. The pilot study demonstrates the effectiveness of a starch-based edible coating formulation for improving the ambient storage capacity of banana fruit.

Pre-storage treatment of mechanically-injured green pepper (Capsicum annuum L.) fruit with putrescine reduces adverse physiological responses

Green peppers are vulnerable to mechanical damage during harvesting and postharvest storage and transportation that significantly decreases their quality and economic value. In the present study, the effects of a pre-storage exogenous application of 1 mmol L−1 putrescine (Put) was assessed by the postharvest physiology indicators of two cultivars of mechanically-injured green pepper (‘Nongda 24’ and ‘Jingtian 3’) stored at 20 °C. Results indicated that, compared to control, Put treatment effectively maintained the quality of the green peppers by suppressing the change in fruit color from green to red, maintaining higher fruit firmness, decreasing electrolyte leakage, reducing the degradation of vitamin C and chlorophyll, and inhibiting the accumulation of malondialdehyde. The relative gene expression and enzyme activity of peroxidase, catalase, and ascorbate peroxidase were enhanced by Put. The collective data indicates that Put reduces the adverse physiological changes in pepper fruits caused by mechanical injury. The use of Put may provide a method to reduce food wastage and economic losses in the production and marketing of green peppers.

Effect of abscisic acid (ABA) and chitosan/nano-silica/sodium alginate composite film on the color development and quality of postharvest Chinese winter jujube (Zizyphus jujuba Mill. cv. Dongzao)

The color change of the jujube fruit after harvest is used as a quality indicator. The effects of abscisic acid (ABA) and a chitosan/nano-silica/sodium alginate composite film on the color development and qualitative properties of harvested jujube in cold storage were investigated. The results indicate that a composite film could prolong the shelf life of post-harvested winter jujube for approximately 1 month, while the ABA treatment induced ripening and reduced the quality. A significant positive correlation between the a∗/b∗ values, water loss and the malondialdehyde (MDA) content was found for fruits in cold storage. In comparison with the control and ABA-treated fruit, superoxide dismutase (SOD), polyphenol oxidase (PPO) and peroxidase (POD) activities were lower than those in a composite film-treated fruit. In addition, the dihydroflavonol-4-reductase (DFR) is the primary gene that regulates the expression of anthocyanin.