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A limited number of studies have examined how drying conditions affect the cannabinoid and terpene content in cannabis inflorescences. In the present study, we evaluated the potential of controlled atmosphere drying chambers for drying medicinal cannabis inflorescence. Controlled atmosphere drying chambers were found to reduce the drying and curing time by at least 60% compared to traditional drying methods, while preserving the volatile terpene content. On the other hand, inflorescences subjected to traditional drying were highly infested by Alternaria alternata and also revealed low infestation of Botrytis cinerea. In the high-THC chemovar ("240"), controlled N2 and atm drying conditions preserved THCA concentration as compared to the initial time point (t0). On the other hand, in the hybrid chemovar ("Gen12") all of the employed drying conditions preserved THCA and CBDA content. The optimal drying conditions for preserving monoterpenes and sesquiterpenes in both chemovars were C5O5 (5% CO2, 5% O2, and 90% N2) and pure N2, respectively. The results of this study suggest that each chemovar may require tailored drying conditions in order to preserve specific terpenes and cannabinoids. Controlled atmosphere drying chambers could offer a cost-effective, fast, and efficient drying method for preserving cannabinoids and terpenes during the drying process while reducing the risk of mold growth. [ABSTRACT FROM AUTHOR]

BACKGROUND Terpene, eugenol and polyphenolic contents of basil are major determinants of quality, which is affected by genetics, weather, growing practices, pests and diseases. Here, we aimed to develop a simple predictive analytical method for determining the polyphenol, eugenol and terpene content of the leaves of major Israeli sweet basil cultivars grown hydroponically, as a function of harvest time, through the use of near‐infrared (NIR) spectroscopy, liquid/gas chromatography, and chemometric methods. We also wanted to identify the harvest time associated with the highest terpene, eugenol and polyphenol content. RESULTS: Six different cultivars and four different harvest times were analyzed. Partial least square regression (PLS‐R) analysis yielded an accurate, predictive model that explained more than 93% of the population variance for all of the analyzed compounds. The model yielded good/excellent prediction (R2 > 0.90, R2cv and R2pre > 0.80) and very good residual predictive deviation (RPD > 2) for all of the analyzed compounds. Concentrations of rosmarinic acid, eugenol and terpenes increased steadily over the first 3 weeks, peaking in the fourth week in most of the cultivars. Our PLS‐discriminant analysis (PLS‐DA) model provided accurate harvest classification and prediction as compared to cultivar classification. The sensitivity, specificity and accuracy of harvest classification were larger than 0.82 for all harvest time points, whereas the cultivar classification, resulted in sensitivity values lower than 0.8 in three cultivars. CONCLUSION: The PLS‐R model provided good predictions of rosmarinic acid, eugenol and terpene content. Our NIR coupled with a PLS‐DA demonstrated reasonable solution for harvest and cultivar classification. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The regulatory effects of 2.5 kPa CO[sub2] and the ethylene action inhibitor, 1-methylcyclopropene (1-MCP), at 0.7 μmol 1[sup-1], were assessed on accelerated senescence in post-harvest basil (Ocimum basilicum L.). Three indicators of quality deterioration: browning, leaf decay, and leaf abscission were evaluated visually and scored on indices linking the onset and progression of senescence to marketability. In control sprigs not exposed to ethylene, moderately raised levels of CO[sub2] were found to reduce browning and decay. Pre-treatment with 1-MCP alone reduced browning, but not decay. Exogenous ethylene accelerated leaf browning and decay only slightly, but caused unacceptably high rates of leaf abscission. Pre-treatment with 1-MCP was found to be more effective than CO[sub2] at inhibiting the enhancing effect of exogenous ethylene on leaf abscission. However, the combined treatment had a significant effect in completely preventing ethylene-induced leaf abscission. Exposure of basil sprigs to exogenous ethylene resulted in an increased production of endogenous ethylene, which increased greatly following pre-treatment with 1-MCP and, to a lesser extent, in CO[sub2]-treated sprigs. [ABSTRACT FROM AUTHOR]

Abstract: The regulatory effects of 5kPa CO2 and of the ethylene action inhibitor, 1-methylcyclopropene (1-MCP) at 0.5μmol/l on the senescence of harvested mint, Mentha longifolia L. were assessed. Visual parameters of senescence including yellowing, browning, decay and leaf abscission were recorded and scored on scales linking the onset and progression of senescence to marketability. The effects of plant age on the rate of postharvest senescence and on the efficacy of the CO2 and 1-MCP treatments were also investigated. All experiments were repeated with and without the presence of exogenous ethylene. Two experimental formats were used, with 6 days storage at room temperature representing local market conditions, and 6 days cold storage at 1.5°C followed by 4 days at room temperature representing export market conditions. Sprigs from old plants were no longer of marketable quality after 6 days storage at room temperature. Exogenous ethylene accelerated the onset of senescence causing unacceptably high rates of leaf abscission. Raised levels of CO2 in a controlled atmosphere system were found to be more effective in inhibiting senescence without the presence of exogenous ethylene than pre-treatment with 1-MCP, and no additive effect was found. However in the presence of exogenous ethylene, a combined treatment with 1-MCP together with raised CO2 levels resulted in a significant additive effect in nullifying the ethylene-induced leaf abscission. Respiration rates as measured by CO2 production, and ethylene production, were recorded throughout all experiments. While CO2 levels were not affected by any experimental treatment, ethylene production was elevated in mint sprigs exposed to an initial dose of gaseous 1-MCP, and was further increased under a combined treatment of 1-MCP together with 5kPa CO2. However in the presence of exogenous ethylene, CO2 strongly suppressed the 1-MCP induced ethylene production. [Copyright &y& Elsevier]

Grafting of vegetable plants is done primarily to reduce the potential for damage caused by soil-borne diseases. Most of the watermelons (Citrullus) grown in the Mediterranean Basin, including in Israel, are grafted, mainly on interspecific hybrid pumpkin (Cucurbita) rootstocks. Biblical law (Leviticus 19:19) does not allow intergeneric grafting, so in recent years, great efforts have been made in Israel to find or breed watermelon rootstocks. Both interspecific and intergeneric grafting can have negative or positive effects on fruit yield and quality after harvest. The inconsistencies in fruit quality and shelf-life parameters can be attributed to differences in production environments. However, many farmers are grafting and planting the same rootstock-scion combination all over the country, regardless of local soil, water, and climactic conditions. We studied the effect of similar rootstock-scion combinations on watermelon yield and fruit quality in three regions of Israel differing in soil type and altitude. Fruit-quality parameters were evaluated after 4 days at 21 °C (local marketing simulation). Fruit quality was significantly affected, mainly by the growing region, based on factorial analysis, but also by rootstock-scion combination, regardless of rootstock vigor. Therefore, the best rootstock-scion combination needs to be found and adopted for each growing region. Grafting was essential for watermelon crop survival in contaminated soils and improved both plant performance and postharvest fruit quality, but was not a factor in non-contaminated soils. [ABSTRACT FROM AUTHOR]