Application and toxicity studies of arabinoxylan and β-d-glucan stearic acid ester composite coatings in extending postharvest storage of peach

Peaches are good source of nutrients and known for their taste and aroma. The highly perishable nature of the peaches tends to decay rapidly during transportation and storage is a serious constraint for efficient transportation and storage. Therefore, the effect of arabinoxylan (AX) and β-D-glucan stearic acid ester (SABG) composite coating material was examined for the postharvest storage quality of peach under storage at 22 ± 2 °C with 85% relative humidity (RH). Both, AX-SABG and shellac (1–2%) coatings significantly reduced the change in the quality attributes like weight loss (1.2–1.4 fold), respiration rate (1.1–1.2 fold), ripening index (1.3–1.5 fold) and firmness (1.3–1.5 fold) during 6 days storage as compared to the uncoated peaches. In addition, AX-SABG (1–2%) coating was more effective in retaining aroma volatiles and reducing disease incidence compared to shellac. Further, acute and chronic toxicological studies have shown no tissue related toxicity and mortality in mice. Our results suggest that AX-SABG as an edible coating has the potential to preserve the fruit quality during 6 days storage at 22 ± 2 °C and extend the postharvest shelf life of peach during storage.

RNAseq reveals different transcriptomic responses to GA3 in early and midseason varieties before ripening initiation in sweet cherry fruits

Gibberellin (GA) negatively affects color evolution and other ripening-related processes in non-climacteric fruits. The bioactive GA, gibberellic acid (GA3), is commonly applied at the light green-to-straw yellow transition to increase firmness and delay ripening in sweet cherry (Prunus avium L.), though causing different effects depending on the variety. Recently, we reported that GA3 delayed the IAD parameter (a ripening index) in a mid-season variety, whereas GA3 did not delay IAD but reduced it at ripeness in an early-season variety. To further explore this contrasting behavior between varieties, we analyzed the transcriptomic responses to GA3 applied on two sweet cherry varieties with different maturity time phenotypes. At harvest, GA3 produced fruits with less color in both varieties. Similar to our previous report, GA3 delayed fruit color initiation and IAD only in the mid-season variety and reduced IAD at harvest only in the early-season variety. RNA-seq analysis of control- and GA3-treated fruits revealed that ripening-related categories were overrepresented in the early-season variety, including ‘photosynthesis’ and ‘auxin response’. GA3 also changed the expression of carotenoid and abscisic acid (ABA) biosynthetic genes in this variety. In contrast, overrepresented categories in the mid-season variety were mainly related to metabolic processes. In this variety, some PP2Cs putative genes were positively regulated by GA3, which are negative regulators of ABA responses, and MYB44-like genes (putative repressors of PP2Cs expression) were downregulated. These results show that GA3 differentially modulates the transcriptome at the onset of ripening in a variety-dependent manner and suggest that GA3 impairs ripening through the modification of ripening associated gene expression only in the early-season variety; whereas in the mid-season variety, control of the ripening timing may occur through the PP2C gene expression regulation. This work contributes to the understanding of the role of GA in non-climacteric fruit ripening.

Quality Attributes and Storage of Tomato Fruits as Affected by an Eco-Friendly, Essential Oil-Based Product

The preservation of fresh produce quality is a major aim in the food industry since consumers demand safe and of high nutritional value products. In recent decades there has been a turn towards the use of eco-friendly, natural products (i.e., essential oils-EOs) in an attempt to reduce chemical-based sanitizing agents (i.e., chlorine and chlorine-based agents). The aim of this study was to evaluate the efficacy of an eco-friendly product (EP—based on rosemary and eucalyptus essential oils) and two different application methods (vapor and dipping) on the quality attributes of tomato fruits throughout storage at 11 °C and 90% relative humidity for 14 days. The results indicated that overall, the EP was able to maintain the quality of tomato fruits. Dipping application was found to affect less the quality attributes of tomato, such as titratable acidity, ripening index and antioxidant activity compared to the vapor application method. Vapor application of 0.4% EP increased fruit’s antioxidant activity, whereas tomatoes dipped in EP solution presented decreased damage index (hydrogen peroxide and lipid peroxidation levels), activating enzymes antioxidant capacity (catalases and peroxidases). Moreover, higher EP concentration (up to 0.8%) resulted in a less acceptable product compared to lower concentration (0.4%). Overall, the results from the present study suggest that the investigated EP can be used for the preservation of fresh produce instead of the current commercial sanitizing agent (chlorine); however, the method of application and conditions of application must be further assessed for every commodity tested.

Effect of different foliar particle films (kaolin and zeolitite) on chemical and sensory properties of olive oil

<p>During the growing season, the use of foliar treatments based on fine grained geomaterial to reduce the negative impact of environmental stresses and protect the olives from insect pests is a well-known approach; however, while kaolin powders have been widely employed, zeolitite-based materials are much less known and exploited.</p><p>The aim of this study is to assess the effect of the two different treatments (zeolitite and kaolin) on the chemical and sensory qualities of the oils produced.</p><p>The study was carried out during two consecutive crop seasons in a 15 year old commercial olive orchard (Olea europaea), cv Correggiolo, located on the Appennine hills near Bologna (Italy). Foliar treatments were distributed during summer, until olive harvest. Ripening index, weight, oil and water content were measured on olive fruits. Olive productions were transformed in oils using a low scale continuous mill, quality parameters (free acidity, peroxide numbers, K232, K270, total phenols, fatty acids) were evaluated according to the official methods described in Regulation EC 2568/91 and subsequent amendments. Phenolic compounds, vitamins and pigments were determined by HPLC-DAD. Sensory analysis was performed by the panel of Agency for Agrofood Sector Services of Marche region (ASSAM), a fully-trained analytical taste panel recognized by the International Olive Oil Council (IOC) of Madrid, Spain, and by the Italian Ministry for Agriculture, Food, and Forestry Policy.</p><p>Olives treated with zeolite showed higher oil contents with respect to the other treatments. Oils produced by plants treated with zeolite particle film exhibited higher contents of total phenols, tyrosol, oleuropein and secoiridoids than to the oils produced by other treatments. Oils produced from olives treated with kaolin had sensory profiles characterized by sweet notes ascribable to ripe fruits, the tasters perceived notes of berries that are not typical of the Correggiolo cultivar.</p><p>The sensory taint test revealed a statistically significant difference between oils produced from olives treated with kaolin and the control, whereas no difference emerged between oils obtained from olives treated with zeolite and the control.</p><p>Particle film can influence some physiological plant parameters (photosynthesis, transpiration, water use efficiency) and, by consequence, it has also an influence on olive and oil quality. Olive plants treated with zeolite produced oils with higher antioxidant endowment, while oils produced from plants treated with kaolin were characterized by lower phenolic contents. Moreover, the kaolin treatment significantly affected the organoleptic properties of oils.</p>

Citral Delays Postharvest Senescence of Kiwifruit by Enhancing Antioxidant Capacity under Cold Storage

Citral is an aliphatic aldehyde extracted from citrus essential oil. The aim of the study was to examine how citral treatment affects the weight loss, firmness, respiration, and ripening index, as well as the antioxidant capacity of kiwifruit (Actinidia chinensis cv. ‘Jinkui’). The citral treatment was seen to reduce the weight loss, softening, and fruit respiration compared to control fruits. Citral treatment also had an inhibitory effect on ripening index, O2•− production rate, and malondialdehyde (MDA) accumulation. The degradations of ascorbic acid (AsA) content, total flavonoids content (TFC), and total phenolics content (TPC) were also suppressed by citral. In contrast, citral treatment induces the activation of antioxidant enzyme system such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). Collectively, the results indicated that citral treatment delays postharvest senescence and prolongs storage life by enhancing antioxidant capacity in harvested kiwifruits. These findings suggest that citral has the potential to be used as a promising natural preservative for the extension of postharvest quality in harvested kiwifruit.

RNA-seq analysis reveals different transcriptomic responses to GA3 in early- and mid-season varieties before ripening initiation in sweet cherry (Prunus avium L.) fruits

Gibberellin (GA) negatively affects color evolution and other ripening-related processes in non-climacteric fruits. The bioactive GA, gibberellic acid (GA3), is commonly applied at the light green-to-straw yellow transition to increase firmness and delay ripening in sweet cherry (Prunus avium L.), though causing different effects depending on the variety. Recently, we reported that GA3 delayed the IAD parameter (a ripening index) in a mid-season variety, whereas GA3 did not delay IAD but reduced it at ripeness in an early-season variety. To further explore this contrasting behavior between varieties, we analyzed the transcriptomic responses to GA3 applied on two sweet cherry varieties with different maturity time phenotypes. At harvest, GA3 produced fruits with less color in both varieties. Similar to our previous report, GA3 delayed fruit color initiation and IAD only in the mid-season variety, and reduced IAD at harvest only in the early-season variety. RNA-seq analysis of control- and GA3-treated fruits of both varieties revealed that ripening related categories were overrepresented in the early-season variety, including 'photosynthesis' and 'auxin response.' GA3 also changed the expression of carotenoid and abscisic acid (ABA) biosynthetic genes in this variety. In contrast, overrepresented categories in the mid-season variety were related mainly to metabolic processes. In this variety, some PP2Cs putative genes were positively regulated by GA3, which are negative regulators of ABA responses. This was accompanied with downregulation of MYB44-like genes, putative repressors of PP2Cs expression. These results show that GA3 differentially modulates the transcriptome at the onset of ripening in a variety-dependent manner and suggest that GA3 impairs ripening through the modification of ripening associated gene expression only in the early-season variety; whereas in the mid-season variety, possibly a control of the ripening timing occurs through the PP2C gene expression regulation. This work contributes to the understanding of the role of GA in non-climacteric fruit ripening.

Harvest Maturity Influences Fruit Quality of Carambola (Averrhoa carambola L.)

Harvest maturity determines the shelf life and nutritional quality of fruits. The present study was planned to determine the effect of harvest maturity on fruit quality of carambola. Fruits of carambola (Averrhoa carambola L.) cv. “Arkin” were harvested at five maturity stages, i.e., M1 (100% green), M2 (75% green and 25% yellow), M3 (50% green and 50% yellow), M4 (25% green and 75% yellow), and M5 (100% yellow) and subjected to physico-chemical analysis. At eating soft stage, a significant linear increase in fruit juice percentage, total soluble solids (TSS), ripening index (TSS/TA) and fruit juice pH, while a decrease in rag content, ascorbic acid (vitamin C) and titratable acidity (TA) was observed as the maturity progressed from 100% green to 100% yellow. Sensory evaluation data of fruit skin colour, flavour, texture, and acceptability showed the highest score for fruits harvested at 25% green and 75% yellow (M4) stage. In conclusion, harvest maturity significantly influenced various biochemical quality characteristics and carambola fruits harvested at 75% yellow (M4) is considered as an optimal harvest stage that exhibited best sensory and nutritional quality attributes.

Gibberellic Acid Modifies the Transcript Abundance of ABA Pathway Orthologs and Modulates Sweet Cherry (Prunus avium) Fruit Ripening in Early- and Mid-Season Varieties

Several phytohormones modulate ripening in non-climacteric fruits, which is triggered by abscisic acid (ABA). Gibberellins (GAs) are present during the onset of ripening in sweet cherry fruits, and exogenous gibberellic acid (GA3) application delays ripening, though this effect is variety-dependent. Although an ABA accumulation delay has been reported following GA3 treatment, the mechanism by which GA modulates this process has not been investigated at the molecular level in sweet cherry. Therefore, the aim of this work is to analyze the effect of GA3 on the fruit ripening process and the transcript levels of ABA pathway orthologs in two varieties having different maturity time phenotypes. The early-season variety had a rapid transition from yellow to pink fruit color, whereas pink color initiation took longer in the mid-season variety. GA3 increased the proportion of lighter colored fruits at ripeness in both varieties, but it produced a delay in IAD—a ripening index—only in the mid-season variety. This delay was accompanied by an increased transcript abundance of PavPP2Cs, which are putative negative regulators of the ABA pathway. On the other hand, the early-season variety had increased expression of PavCYP707A2—a putative ABA catabolic gene–, and reduced transcript levels of PavPP2Cs and SnRK2s after the GA3 treatment. Together these results show that GA modulates fruit ripening, exerting its action in part by interacting with the ABA pathway in sweet cherry.

Comparative studies on pigmented grapefruit (Citrus paradisi Macf.) cultivars under climatic conditions of Sahiwal, Punjab

Four pigmented grapefruit cultivars viz. Shamber, Flame, Star Ruby and Rio Red were evaluated at Horticultural Research Station, Sahiwal (Pakistan) for their production features encompassing growth, yield and fruit characteristics. The cultivars significantly differed for the studied physical parameters i.e. yield per plant (kg), fruit weight (g), fruit length (cm), fruit breadth (cm), peel thickness (mm), peel, juice and rag contents (%)], and biochemical traits i.e. TSS (°Brix), acidity (%) and ripening index. The highest fruit yield (84.28 kg/plant) was recorded for Star Ruby and the minimum (75.00 kg/plant) was recorded for Rio Red. The maximum fruit weight (338.92 g/fruit) was noted in Rio Red, while the maximum fruit length (9.14 cm) was found in Shamber. The highest TSS was noted for Rio Red (8.32 °Brix) followed by Shamber (7.94 °Brix). The maximum fruit acidity was observed for Star Ruby (1.00%), while the minimum for Shamber (0.94%). It was concluded that four grapefruit cultivars under consideration were divergent in their performance under prevailing conditions.