Impact of 24-epibrassinoliode and methyl jasmonate on quality of Red Delicious apples.

BACKGROUND: Changes in apple fruit quality indices in response to foliar spray with 24-epibrassinolide (EBL) at 0 and 1 µmol L-1 and methyl jasmonate (MeJA) at 0 and 0.5 µmol L-1 , as well as the combination of these phytohormones, were investigated at harvest and during cold storage. RESULTS: Both phytohormones synergistically enhanced the fruit firmness, specific weight, size, fresh weight, water content, total antioxidant activity, total phenolics, ascorbic acid, total anthocyanins, total soluble solids/titratable acidity ratio and precocity. In addition, the fruit abscission pattern was changed in response to different treatments. Treated fruit exhibited lower weight loss and internal breakdown symptoms and higher total soluble solids index, firmness and phytochemicals during cold storage. A negative correlation was seen between fruit mass, firmness, specific weight, antioxidant activity, total phenolics and vitamin C content with internal breakdown occurrence and weight loss. CONCLUSION: Foliar spray with EBL and MeJA during the growth season is a good environmental friendly and safe method for enhancing the apple fruit different quality parameters, marketability and postharvest life. © 2023 Society of Chemical Industry.

Nitric oxide alleviates chilling injury by regulating the metabolism of lipid and cell wall in cold-storage peach fruit.

Peach fruit are prone to development of chilling injury during cold storage at around 0-7 °C. Nitric oxide (NO) has been proven to alleviate chilling injury, but the mechanism was still unclear. In this study, peach fruit were immersed in a NO donor (sodium nitroprusside, SNP) solution for 10 min, then stored at 0 °C. The SNP alleviated chilling injury, including decreasing the internal browning index, malondialdehyde content, electrolyte leakage, and lipoxygenase activity, and maintaining firmness. Furthermore, SNP maintenance of fruit firmness was associated with reduction of xyloglucan endotransglycosylase/hydrolase family member gene expression and decrease of cell wall hydrolase activity, especially the activities of polygalacturonase, xyloglucan endoglycosyl transferase, cellulase, and ß-galactosidase. Meanwhile, SNP regulated the lipid metabolism by up-regulating the expression of genes encoding glycerol-3-phosphate acyltransferase, ketoacy-ACP synthase, phosphatidylinositol bisphosphate and long-chain acyl-CoA. Thus, the results of this study indicate that SNP alleviates chilling injury of post-harvest peach fruit by regulating cell wall and lipid metabolism.

Efeito de tratamentos com altas concentrações de CO2 sobre a qualidade de maçãs 'Golden delicious' armazenadas em atmosfera controlada / Effect of treatment with high CO2 concentrations on quality of 'Golden delicious' apples stored in controlled atmosphere

O experimento teve por objetivo avaliar a influência das altas concentrações iniciais de CO2 sobre os aspectos físico-químicos de maçãs 'Golden Delicious' armazenadas em atmosfera controlada. Os tratamentos foram 10% de CO2 e 5% de O2 e 15% de CO2 e 5% de O2 durante 5, 10 e 15 dias, sendo que durante o restante do período de armazenamento os frutos foram armazenados em 4% de CO2 e 1,5% de O2, na temperatura de +0,5 °C e umidade relativa de 97%. Após 10 meses, não foi verificado diferenças significativas na firmeza de polpa, acidez titulável, sólidos solúveis totais e controle de podridões. Na abertura das câmaras os tratamentos iniciais com CO2 não mostraram influência na degenerescência da polpa e escaldadura, porém, após 14 dias todos os tratamentos com CO2 aumentaram a incidência de degenerescência interna e tratamentos com 15% de CO2 diminuíram ligeiramente a ocorrência da escaldadura.

The aim of this experiment was to evaluate the effect of initial high CO2 concentrations on quality of 'Golden Delicious' apples stored in controlled atmosphere. The treatments were 10% of CO2, and 5% of O2, and 15% of CO2, and 5% of O2, during 5, 10 and 15 days but during the remaining of storage time fruits were kept in 4% of CO2, and 1.5% of O2, at +0,5 °C and 97% RH. After 10 months, no diferences in firmness, total soluble solids contents, acidity and decay were observed. At opening of controlled atmosphere chambers CO2 treatment had no influence in internal breakdown and scald, but after 14 days in shelf-life. all treatments with high CO2 increased internal breakdown and 15% of CO2 decreased scald incidence.