Harvesting Maturity Assessment of Newly Developed Citrus Hybrids (Citrus maxima Merr. × Citrus sinensis (L.) Osbeck) for Optimum Juice Quality.

The assessment of the optimum harvesting stage is a prerequisite to evaluating the performance of new citrus genotypes. The intrinsic and extrinsic fruit quality traits of citrus fruits change throughout their developmental process; therefore, to ensure the highest quality, the fruit must be harvested at an appropriate stage of maturity. The biochemical changes in terms of total soluble solids (TSS), titratable acidity (TA), TSS/TA ratio, BrimA (Brix minus acidity), and ascorbic acid, in addition to the organoleptic acceptability of 16 new interspecific citrus hybrids, were evaluated in New Delhi (India) during the H1-H8 harvesting stage at 15-day intervals to standardize the optimum harvesting stage. The TA and ascorbic acid content were at a maximum level during the early harvesting stage and declined with time, reaching the minimum level in the last harvesting stage. The TSS, TSS/TA ratio, and BrimA values were found to have an increasing trend up to the last stage in most of the hybrids. The juice content shows an inclining trend during the initial harvesting observations, followed by stable juice content and then a decline. The BrimA was found to be a better predictor for consumer acceptability compared to the traditional maturity index TSS/TA ratio and, thus, harvesting maturity. Specific TSS, TA, and BrimA values, in addition to the juice percentage and ascorbic acid content, corresponding to the highest hedonic score, were judged as the optimum harvesting stage indicators for an individual hybrid genotype. Among the interspecific hybrids, SCSH-9-10/12, SCSH-11-15/12, and SCSH-17-19/13 were found to be superior, having better juice acceptability organoleptic scores (≥6.0) and higher juice content (≥40%). Principal component analysis based on fruit physico-chemical traits could be able to distinguish the optimum maturity stage in all of the citrus genotypes.

Large-Scale, High-Throughput Phenotyping of the Postharvest Storage Performance of 'Rustenburg' Navel Oranges and the Development of Shelf-Life Prediction Models.

We conducted a large-scale, high-throughput phenotyping analysis of the effects of various pre-harvest and postharvest features on the quality of 'Rustenburg' navel oranges, in order to develop shelf-life prediction models to enable the use of the First Expired, First Out logistics strategy. The examined pre-harvest features included harvest time and yield, and the examined postharvest features included storage temperature, relative humidity during storage and duration of storage. All together, we evaluated 12,000 oranges (~4 tons) from six different orchards and conducted 170,576 measurements of 14 quality parameters. Storage time was found to be the most important feature affecting fruit quality, followed by storage temperature, harvest time, yield and humidity. The examined features significantly affected (p < 0.001) fruit weight loss, firmness, decay, color, peel damage, chilling injury, internal dryness, acidity, vitamin C and ethanol levels, and flavor and acceptance scores. Four regression models were evaluated for their ability to predict fruit quality based on pre-harvest and postharvest features. Extreme gradient boosting (XGBoost) combined with a duplication approach was found to be the most effective approach. It allowed for the prediction of fruit-acceptance scores among the full data set, with a root mean square error (RMSE) of 0.217 and an R2 of 0.891.

Effects of packinghouse operations on the flavor of 'Orri' mandarins.

Mandarins have a delicate flavor and are easy to peel and easy to consume. However, they are relatively perishable and suffer from flavor deterioration after harvest. The goal of the current study was to examine the effects of commercial packinghouse operations on the flavor of 'Orri' mandarins. For that purpose, we collected fruit from four different points along a commercial citrus packing line: (1) directly from the harvest bin, (2) after application of a hot (53°C) fungicide treatment for 30 s, (3) after waxing, and (4) after waxing and after the fruit had passed through a hot-air drying tunnel (37°C) for 2 min. The collected fruit were stored for 3 or 6 weeks at 5°C and then kept for five more days under shelf-life conditions at 22°C. The observed results indicate that the hot fungicide treatment had no effect on flavor quality. However, the waxing and waxing +drying treatments resulted in significant increases in ethanol accumulation, lower flavor-acceptability scores, and increased off-flavors. Gas-chromatography mass-spectrometry (GC-MS) analysis revealed that the waxing and waxing +drying treatments resulted in particular increases in the levels of alcohol and ethyl ester volatiles; whereas levels of other aroma volatiles (i.e., esters, aldehydes, monoterpenes, and sesquiterpenes) decreased after storage in all fruit samples. Overall, the waxing process in commercial citrus packinghouses increased ethanol and ethyl ester volatile levels and harmed flavor acceptability. These findings demonstrate the need to identify new wax formulations that do not hamper fruit-flavor quality.

Microperforated Compostable Packaging Extends Shelf Life of Ethylene-Treated Banana Fruit.

Plastic packaging preserves the quality of ethylene-treated bananas by generating a beneficial modified atmosphere (MA). However, petroleum-based plastics cause environmental pollution, due to their slow decomposition. Biodegradable packaging may help resolve this controversy, provided it shows adequate preservation efficacy. In this study, we tested the compostable biodegradable polyester packaging of ethylene-treated bananas in comparison with commercially available petroleum-based plastic alternatives. When compostable packaging was used in a non-perforated form, it caused hypoxic fermentation, manifested as impaired ripening, off-flavor, and excessive softening. Micro-perforation prevented fermentation and allowed MA buildup. Furthermore, no water condensation was observed in the biodegradable packages, due to their somewhat higher water vapor permeability compared to conventional plastics. The fruit weight loss in biodegradable packaging was higher than in polypropylene, but 3-4-fold lower than in open containers. The control of senescence spotting was the major advantage of microperforated biodegradable packaging, combined with the preservation of acceptable fruit firmness and flavor, and low crown rot incidence. Optimal biodegradable packages extended the shelf life of bananas by four days compared with open containers, and by two days compared with the best commercial plastic package tested. Microperforated biodegradable packages combined the advantage of improved sustainability with superior fruit preservation.

Retaining red bell pepper quality by perforated compostable packaging.

Retail packages are widely used to preserve pepper fruit quality. However, due to the negative impact of conventional plastics on the environment there is an urgent need to replace these packaging materials with recyclable or compostable alternatives. Hereby, we evaluated the effects of compostable modified atmosphere packages with different perforation rates on keeping the quality of red bell pepper fruit during extended shelf life and simulated supply chain conditions. The results indicated that micro-perforated (µP) compostable packages creating an atmosphere of 15%-18% O2 and 2%-5% CO2, as well as macro-perforated (MP) compostable packages creating an atmosphere of 20%-21% O2 and 0.1%-0.5% CO2, effectively retained red bell pepper quality by reducing fruit weight loss, shriveling and softening, and by retaining flavor acceptance and visual appearance. On the other hand, nonperforated compostable packages resulted in the creation of anaerobic conditions (O2 < 1% and CO2 > 9%), and harmed produce quality as manifested by enhanced softening, decay, peel damage, and off-flavors. Overall, µP and MP compostable packages extended pepper fruit shelf life from 1 week to 3 weeks under continuous shelf life conditions, and from 2 weeks to 4 weeks under simulated supply chain and refrigerated storage conditions.

Effects of Compostable Packaging and Perforation Rates on Cucumber Quality during Extended Shelf Life and Simulated Farm-to-Fork Supply-Chain Conditions.

Cucumbers are highly perishable and suffer from moisture loss, shriveling, yellowing, peel damage, and decay. Plastic packaging helps to preserve cucumber quality, but harms the environment. We examined the use of compostable modified atmosphere packaging (MAP) with different perforation rates as a possible replacement for conventional plastic packaging materials. The results indicate that all of the tested types of packaging reduced cucumber weight loss and shriveling. However, compostable MAP with micro-perforations that created a modified atmosphere of between 16-18% O2 and 3-5% CO2 most effectively preserved cucumber quality, as demonstrated by reduced peel pitting, the reduced appearance of warts and the inhibition of yellowing and decay development. Overall, micro-perforated compostable packaging extended the storage life of cucumbers under both extended shelf conditions and simulated farm-to-fork supply-chain conditions and thus may serve as a replacement for the plastic packaging currently used to preserve the postharvest quality of cucumbers.

Covalent linkage of bioactive volatiles to a polysaccharide support as a potential approach for preparing active edible coatings and delivery systems for food products.

In this study, a potential of covalent linkage approach for developing active edible coatings was examined. Vanillin and trans-cinnamaldehyde were bound to chitosan by Schiff base reaction and reductive amination. The modified polysaccharides were comprehensively characterized and applied as active coatings on fresh-cut melon. The covalent linkage allowed overcoming solubility problems with the lipophilic vanillin and cinnamaldehyde and neutralizing their volatility, producing well-adhered coatings that enhanced fruit quality and storability without sensorial impairment. The attached hydrophobic moieties also provided new polysaccharides with self-assembling ability. Their aggregates were loaded with antimicrobial citral and added to mandarin juice, resulting in up to 6 log CFU/mL microbial count reduction. Thus, the covalent linkage concept offers several advantages, especially when hydrophobic or volatile active agents are used. Further developed, it may become a safe and effective tool for the formation of advanced active edible coatings and delivery vehicles for direct applications on food products.

Effects of nitrogen fertilization on pomegranate fruit, aril and juice quality.

BACKGROUND: Nitrogen (N) fertilization influences plant growth and yield, and may also affect fruit quality. For two consecutive seasons, we examined the effects of various N fertilization levels - 5 to 200 mg L-1  - on pomegranate fruit, aril and juice quality. Evaluations included fruit and aril weight, size and color, appearance of peel blemishes, internal black rot and nutritional composition of extracted juices. RESULTS: Nitrogen fertilization affected pomegranate fruit, aril and juice quality. The most pronounced effects were observed in trees grown under the lowest N fertilization level, which bore smaller fruit and arils, the latter with lighter color; the fruit suffered from sunburn, and the juice had lower total soluble solid, acidity and anthocyanin contents. The proportion of edible aril weight per total fruit weight gradually increased with an increase in N fertilization concentration. In contrast, N fertilization did not affect peel color, roughness or cracking incidence. Black rot incidence increased with increasing N concentration. CONCLUSIONS: Nitrogen fertilization affected pomegranate fruit, aril and juice quality, and the total number of marketable fruits per tree. The optimal N fertilization levels, which were most beneficial for achieving high-quality marketable fruit, were between 40 and 100 mg L-1 . © 2019 Society of Chemical Industry.

Molecular mechanisms involved in postharvest chilling tolerance of pomegranate fruit.

Cold storage of pomegranates is essential for prolonging postharvest storage and for the implementation of cold-quarantine insect disinfestation treatments required for international trading. However, pomegranates are chilling sensitive; they may develop chilling injuries upon exposure to unfavorable low temperatures. In this mini-review, we summarize molecular data obtained from three different RNA Seq transcriptome analyses of responses of pomegranate fruits to cold storage. These experiments included comparisons among the transcriptomic responses following a 2-week exposure to 1 °C in three different model systems: 1) unconditioned chilling-sensitive fruits versus relatively chilling-tolerant low-temperature-conditioned fruits; 2) chilling-sensitive early harvested fruits versus relatively chilling-tolerant late-harvested ones; and 3) chilling-sensitive 'Ganesh' variety versus the relatively chilling-tolerant 'Wonderful' variety. Comparisons among differentially expressed transcripts that were exclusively and significantly up-regulated in the relatively chilling-tolerant fruits in all three model systems enabled identification of 573 common chilling tolerance-associated genes in pomegranates. Functional categorization and classification of the differentially expressed transcripts revealed several regulatory, metabolic, and stress-adaptation pathways that were uniquely activated in response to cold storage in relatively chilling-tolerant fruits. More specifically, we identified common up-regulation of transcripts involved in activation of jasmonic acid and ethylene hormone biosynthesis and signaling, stress-related transcription factors, calcium and MAPK signaling, starch degradation and galactinol and raffinose biosynthesis, phenol biosynthesis, lipid metabolism, and heat-shock proteins. We hypothesized these pathways to be involved in imparting chilling tolerance to pomegranate fruits. © 2019 Society of Chemical Industry.

Biochemical and Molecular Factors Governing Peel-Color Development in 'Ora' and 'Shani' Mandarins.

To identify factors governing peel-color development in mandarins, we examined carotenoid content and composition and the expression of carotenoid-related genes during four stages of ripening (i.e., green, breaker, yellow, and orange) in two varieties: 'Ora', which has orange fruit, and 'Shani', which has orange-reddish fruit. The two varieties had different carotenoid compositions, and 'Shani' had a significantly higher level of total carotenoid pigments. 'Shani' was rich in the deep orange ß-cryptoxanthin and the orange-reddish ß-citraurin, whereas 'Ora' was rich in the orange violaxanthin. RNA-Seq analysis revealed significantly greater expression of the carotenoid-biosynthesis genes PSY, ßLCY, ßCHX, and CCD4b, as well as MEP-pathway genes and several ethylene-biosynthesis and -signaling genes in 'Shani' fruit. In contrast, the expression levels of genes involved in the synthesis of α-branch carotenoids (i.e., εLCY and εCHX) and ZEP, which is involved in the formation of violaxanthin, were significantly higher in the 'Ora' fruit.

Diversity among Pomegranate Varieties in Chilling Tolerance and Transcriptome Responses to Cold Storage.

We found great variability in chilling tolerance among 84 pomegranate varieties from the Newe Ya'ar collection; among them, 'Ganesh' was chilling-sensitive, whereas 'Wonderful' was relatively chilling-tolerant. To evaluate the different molecular responses of these varieties to cold storage, we analyzed the transcriptomic changes in the inner membrane tissues of 'Ganesh' and 'Wonderful' fruit after 2 weeks of cold storage at 1 °C. By functional categorization of the differentially expressed transcripts using MapMan, we found that many transcripts related to various pathways, such as jasmonic acid biosynthesis and signaling, galactinol, raffinose, phenol, and phenylpropanoid biosynthesis, calcium and mitogen-activated protein kinase signaling, lipid metabolism, and various transcription factors and heat-shock proteins, have been massively upregulated in 'Wonderful' but not in 'Ganesh' fruit. Thus, it is suggested that these pathways most likely participate in imparting chilling tolerance in pomegranate fruit.

Enhancement of agricultural produce quality and storability using citral-based edible coatings; the valuable effect of nano-emulsification in a solid-state delivery on fresh-cut melons model.

Emulsification approach is widely employed to deliver beneficial agents to liquid food products, whereas utilizing emulsions with solid food is scarce. In this research, coarse and nano emulsions of citral were prepared and embedded in chitosan or carboxymethyl cellulose (CMC) polysaccharides to form active edible coatings for solid-state delivery. Polysaccharides stabilized the emulsions by electrostatic interactions, while chitosan also prevented coalescence. The nano emulsion based films showed a more organized and dense morphology (E-SEM), higher water vapor barrier, better mechanical features (strength, elasticity and Young modulus) than the coarse ones. When applied on a solid food model, fresh-cut melons, the nanoemulsified edible coatings demonstrated a superior antimicrobial protection (up to a 5-log reduction) and significantly extended product's storability (up to 13 days). The presented approach could be further employed for the delivery of other beneficial agents (nutrients, aroma, antimicrobial, antioxidants) to solid food products, contributing a general progress in this field.

Mandarin fruit quality: a review.

During the last decade, there has been a continuous rise in consumption and global marketing of fresh, easy-to-peel mandarins, with current annual production of nearly 29 million tons. Nevertheless, most of the existing knowledge on quality traits of citrus fruit comes from research conducted on oranges and grapefruit, which are the main products for the citrus juice manufacturing industry; relatively little is yet known regarding the unique fruit quality traits of mandarins, nor about the great diversity in these traits among the various natural sub-groups and varieties of mandarins. In the present review we discuss the physiological, biochemical, and molecular factors governing key fruit quality attributes of mandarins, including fruit colour, size and shape, ease of peeling, seedlessness, flavour, and nutritional quality. Fruit colour, size, and shape contribute to external appearance; peelability and seedlessness to ease of consumption; and flavour and nutritional quality to internal quality. © 2017 Society of Chemical Industry.

Distinct Microbiotas are Associated with Ileum-Restricted and Colon-Involving Crohn's Disease.

BACKGROUND: The etiology of inflammatory bowel disease is believed to involve a shift in the microbiota toward more proinflammatory species. Crohn's disease (CD) usually manifests as one of three phenotypes, involving inflammation of the terminal ileum, the colon, or both. However, what determines the particular phenotype and the level of disease activity remains unknown. In this study, we aim to characterize the intestinal microbiota associated with different CD phenotypes. METHODS: DNA was extracted from biopsies of 31 patients with ileal, ileocolic, or colon-restricted CD, and also from 5 non-inflammatory bowel disease control subjects, and analyzed by 16S rRNA gene amplicon pyrosequencing. Data were processed using the Quantitative Insights Into Microbial Ecology pipeline and analyzed using linear discriminant analysis with effect size estimation and PICRUSt algorithms. Two additional recently published cohorts were also analyzed in this study. RESULTS: Highly significant separation was observed between bacterial composition of ileal CD compared with CD with colonic involvement (genus level Bray-Curtis P = 0.005, R = 20%). This separation was unaffected by the biopsy's location or its inflammatory state, or by the patients' condition (remission or relapse). Faecalibacterium was strongly reduced in ileal CD compared with CD with colonic involvement, whereas Enterobacteriaceae were more abundant in the former. Fusobacterium relative abundance was strongly correlated with disease activity in patients with ileal-involving, but not in colon-involving, CD. CONCLUSIONS: Ileal and colon-involving CD sustain distinct microbiotas, suggesting that different mechanisms underlie the two major manifestations of CD. The potential contribution of Fusobacterium to inflammation in ileal CD should be further investigated.

Diversity among mandarin varieties and natural sub-groups in aroma volatiles compositions.

BACKGROUND: Mandarins constitute a large, diverse and important group within the Citrus family. Here, we analysed the aroma volatiles compositions of 13 mandarin varieties belonging to seven genetically different natural sub-groups that included common mandarin (C. reticulata Blanco), clementine (C. clementina Hort. ex. Tan), satsuma (C. unshiu Marcovitch), Mediterranean mandarin (C. deliciosa Tenore), King mandarin (C. nobilis Loureiro), and mandarin hybrids, such as tangor (C. reticulata × C. sinensis) and tangelo (C. reticulata × C. paradisi). RESULTS: We found that mandarin varieties among tangors ('Temple', 'Ortanique'), tangelos ('Orlando', 'Minneola') and King ('King') had more volatiles, at higher levels, and were richer in sesquiterpene and ester volatiles, than other varieties belonging to the sub-groups common mandarin ('Ora', 'Ponkan'), clementine ('Oroval', 'Caffin'), satsuma ('Okitsu', 'Owari') and Mediterranean mandarin ('Avana', 'Yusuf Efendi'). Hierarchical clustering and principal component analysis accurately differentiated between mandarin varieties and natural sub-groups according to their aroma-volatile profiles. CONCLUSIONS: Although we found wide differences in aroma-volatiles compositions among varieties belonging to different natural sub-groups, we detected only minor differences among varieties within any natural sub-group. These findings suggest that selecting appropriate parents would enable manipulation of aroma-volatile compositions in future mandarin breeding programmes.

Sensory and nutritional attributes of pomegranate juices extracted from separated arils and pressed whole fruits.

BACKGROUND: The present study aimed to compare the sensory and nutritional attributes of 'Wonderful' pomegranate juices extracted from separated arils with those from pressed whole fruits. RESULTS: Five different sensory tests were conducted to evaluate the flavor quality of 'Wonderful' pomegranate juices. Consumer acceptance tests revealed that juice from separated arils achieved significantly higher likability scores than that from whole pressed fruits. Furthermore, preference tests revealed that 84% of the tasters preferred the juice extracted from separated arils whereas only 16% preferred the juice from whole pressed fruits. Sensory discrimination tests (triangle tests) revealed that tasters significantly distinguished between the two juices at P ≤ 0.01. Descriptive tests by a trained panel and sensory analysis with an electronic tongue demonstrated that juice from whole pressed fruits was more astringent and had a stronger aftertaste than juice from separated arils. Juice from pressed whole fruits contained significantly higher levels of phenols and hydrolysable tannins, which led to higher astringency. CONCLUSIONS: Pomegranate juice extracted from separated arils was less astringent and more preferred by tasters than juice from whole pressed fruits. Nonetheless, juice from separated arils has lower nutritional benefits.

Diversity in sensory quality and determining factors influencing mandarin flavor liking.

We evaluated the sensory quality of 42 mandarin varieties that belong to 7 different natural subgroups: common mandarin (Citrus reticulata Blanco), Clementine (Citrus clementina Hort. ex. Tan), Satsuma (Citrus unshiu Marcovitch), Mediterranean mandarin (Citrus deliciosa Tenore), King mandarin (Citrus nobilis Loureiro), and mandarin hybrids, such as tangor (Citrus reticulata × Citrus sinensis) and tangelo (Citrus reticulata × Citrus paradisi). Consumer flavor acceptance tests revealed wide diversity in flavor preferences among mandarin varieties and subgroups. Furthermore, descriptive flavor-analysis tests conducted with the aid of a trained sensory panel revealed that the 9 most preferred varieties had similar flavor profiles, characterized by high sweetness, moderate to low acidity levels, low bitterness and gumminess, strong fruity and mandarin flavor, and high juiciness. The average total soluble solids (TSS) and acidity levels among the highly preferred varieties were 13.1% and 1.1%, respectively. In contrast, the 8 least preferred varieties were either too sour or gummy or had low levels of sweetness, fruity, or mandarin flavor, and either high acidity levels (>1.4%) or low TSS levels (<12.0%). Pearson tests revealed significant positive correlations between flavor acceptance and perceptions of sweetness, fruitiness, and mandarin flavor, and negative correlations with acidity levels and perceptions of sourness, bitterness, and gumminess. Principle component analysis clearly distinguished between highly accepted varieties that were tightly correlated with high TSS levels and perceptions of sweetness fruitiness and mandarin flavor, as compared with the least accepted varieties that were correlated with high acidity levels and perceptions of sourness, bitterness, and gumminess.

Development of polysaccharides-based edible coatings for citrus fruits: a layer-by-layer approach.

Biodegradable coatings for citrus fruits that would replace the currently used polyethylene-based waxes, are of great interest. Methylcellulose (MC), hydroxypropyl methylcellulose (HPMC), carboxymethyl cellulose (CMC) and chitosan (CH) coatings were examined on the most sensitive citrus fruit model: mandarins. Among the examined polysaccharides, CMC provided mandarins with the best firmness, lowest weight loss and satisfying gloss, while not affecting natural flavour and the respiration process. To enhance coating performance, glycerol, oleic acid and stearic acid were added; however, mandarin quality generally deteriorated with these additives. Then, a layer-by-layer (LBL) approach was applied. LbL coatings, based on a combination of two polysaccharides, CMC as an internal layer and chitosan as an external layer, gave the best performance. Different concentrations of chitosan were examined. The LbL coatings notably improved all quantified parameters of fruit quality, proving that polysaccharide-based edible coating may offer an alternative to synthetic waxes.

Influence of modified atmosphere packaging on 'Star Ruby' grapefruit phytochemicals.

Modified atmosphere packaging (MAP) can extend the shelf life of salads, vegetables, and fruits by generating a storage environment with low O2, high CO2, and high humidity. The current study investigates the effect of modified atmosphere and humidity generated by two plastic films, microperforated bags (MIPBs) and macroperforated bags (MAPBs), on the levels of phytochemicals present in 'Star Ruby' grapefruits (Citrus paradisi, Macf.) stored for 16 weeks at 10 °C. Control fruits were stored without any packaging film. Juice samples were analyzed every 4 weeks for ascorbic acid, carotenoids, limonoids, flavonoids, and furocoumarins and assessed for quality parameters. MAP significantly reduced weight loss compared to control grapefruits. Control fruits had more ß-carotene, lycopene, and furocoumarin compared with the fruits in MAP. Flavonoid content was highest in fruits stored in MAPB (P < 0.05), while fruits stored in MIPB showed no significant difference in flavonoid content compared to control (P > 0.05). The MAP treatments did not significantly affect ascorbic acid, limonoids, or fruit quality parameters, including total soluble solids, acidity, ripening ratio, decay and disorders, fruit taste, and off-flavors after 16 weeks of storage. These results suggest that MAP can be used to maintain the quality of 'Star Ruby' grapefruit with no detrimental effect on health-promoting phytochemicals.