Superficial scald development in 'Granny Smith' and 'Nicoter' apples: The role of key volatile compounds when fruit are stored under dynamic controlled atmosphere.

A positive correlation of α-farnesene and its oxidation metabolites with superficial scald is commonly reported in apples stored in air or controlled atmosphere (CA) systems, where O2 levels are above the lower oxygen limit (LOL) tolerated by the fruit. Nevertheless, the LOL can be monitored by the dynamic controlled atmosphere (DCA) techniques and to provide different physiological responses. Therefore, this study aimed to evaluate key volatile metabolites from 'Granny Smith' and 'Nicoter' ('Kanzi®') apples stored under dynamic controlled atmosphere (DCA) monitored by respiratory quotient (RQ), i. e. at extremely low oxygen partial pressures (ELO) and correlate their emissions with the incidence of superficial scald (SS). The volatile compounds (VCs) were isolated by solid phase microextraction (HS-SPME) and analyzed by gas chromatography. For the first time, higher concentrations of α-farnesene and its oxidation metabolites (6-methyl-5-hepten-2-one, and 6-methyl-5-hepten-2-ol) were negatively correlated with SS in DCA-RQ. This is likely due to the higher levels of ethanol in fruit stored under this condition having an inhibitory effect on SS incidence even when α-farnesene, 6-methyl-5-hepten-2-one, and 6-methyl-5-hepten-2-ol accumulate. Additionally, SS is more correlated to internal ethylene concentration (IEC) than α-farnesene accumulation and their metabolites, even when fruit were stored under ELO, where ethylene action is reduced.

Key volatile compounds of 'Fuji Kiku' apples as affected by the storage conditions and shelf life: Correlation between volatile emission by intact fruit and juice extracted from the fruit.

For the 'Fuji Kiku' apple, this study aimed: (i) to evaluate the volatile compounds (VCs) from headspace storage chambers with static controlled atmosphere (CA) and with dynamic controlled atmosphere based on chlorophyll fluorescence (DCA-CF) and based on respiratory quotient (DCA-RQ1.5) at ninth month of storage, during 1 and 7 days of shelf life of intact fruit, and in apple juice headspace and (ii) to determine the correlation of the VCs in the headspace from storage chambers and fruit during shelf life with the headspace VCs from apple juice as markers of quality. The VCs were isolated by solid phase microextraction (HS-SPME) and analyzed by gas chromatography. In the storage chambers, ethyl linear chain esters were detected mainly in DCA-RQ1.5, while acetaldehyde and (E)-2-hexenal were more abundant in DCA-CF. At seven days of shelf life, fermentative metabolic compounds had reduced emissions given the opening time of the chamber, while there were higher emissions of branched chain esters, especially ethyl 2-methyl butanoate in DCA-RQ1.5. The correlation was high and positive between the VCs present in the juice and those emitted by the intact fruit during seven days of shelf life, demonstrating that the concentration of VCs in juice can be used to estimate the emissions from whole fruit. DCA-RQ1.5 storage promoted the synthesis of VCs typical of the 'Fuji' apple aroma after a prolonged storage period, even under extremely low partial pressure of oxygen (average 0.15 kPa), contributing to better quality control of characteristic fruit odor and aroma.

Effect of dynamic controlled atmosphere monitored by respiratory quotient and 1-methylcyclopropene on the metabolism and quality of 'Galaxy' apple harvested at three maturity stages.

The objective of this study was to evaluate the interaction between controlled atmosphere (CA), CA+1-methylcyclopropene (1-MCP) and dynamic controlled atmosphere monitored by respiratory quotient (DCA-RQ) with three fruit maturity stages at harvest (early harvest date, optimal harvest date and late harvest date) on 'Galaxy' apple metabolism and quality after harvest and 9months storage plus 7days of shelf life at 20°C. Fruit stored under dynamic controlled atmosphere monitored by respiratory quotient 1.3 (DCA-RQ 1.3) showed lower ethylene production, respiration rate, mealiness and higher flesh firmness in comparison to CA stored fruit, but did not differ from those treated with 1-MCP. The dynamic controlled atmosphere monitored by respiratory quotient 1.5 (DCA-RQ 1.5) increased the acetaldehyde, ethanol and ethyl acetate concentration, regardless of the fruit maturity at harvest. The storage of 'Galaxy' apple under DCA-RQ 1.3 is efficient in keeping quality regardless of the maturity stage at harvest.

Relative humidity and its interaction with the wounds on decay incidence and ripening of 'Galaxy' apples during cold storage / Umidade relativa e sua interação com ferimentos sobre a incidência de podridões e o amadurecimento de maçãs 'Galaxy' durante o armazenamento

The objectives of the present work were control the decay incidence and ripening of wounded fruits by the relative humidity management during the storage. Fruits were allocated in mini experimental chambers at the temperature of 1°C during 5 months. Was verified a significant interaction on ethylene production after 2 and 6 days of shelf life at 20°C. On the evaluation carried out after 6 days, wounded fruits stored under LRH showed lower ethylene production. There was higher mass loss in wounded fruits stored in HRH. Wounded fruits showed high decay incidence. The LRH is not an efficient method to control decay incidence in wounded fruits, but maintain higher flesh firmness, lower ethylene production and respiration rate.

Objetivou-se neste trabalho controlar a ocorrência de podridões e o amadurecimento de frutos com ferimentos pelo manejo da umidade relativa (UR) durante o armazenamento. Os frutos foram acondicionados em minicâmaras experimentais na temperatura de 1°C durante um período de cinco meses. Observou-se uma interação significativa para produção de etileno aos dois e seis dias de exposição a 20°C. Na análise aos seis dias, frutos com ferimento em baixa umidade relativa (BUR) apresentaram menor produção de etileno. Houve maior perda de massa em frutos com ferimento em alta UR. Frutos com ferimento apresentaram elevados índices de podridão. O uso de BUR não é eficiente no controle de podridões em frutos com ferimentos, porém ela mantém maior firmeza de polpa, menor produção de etileno e taxa respiratória.