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Hot Air Treatment (hot + air_treatment)
Selected AbstractsEFFECTS OF PRESTORAGE DRY AND HUMID HOT AIR TREATMENTS ON THE QUALITY, TRIGLYCERIDES AND TOCOPHEROL CONTENTS IN ,HASS' AVOCADO FRUITJOURNAL OF FOOD QUALITY, Issue 2 2004J. DE JESUS ORNELAS P. ABSTRACT ,Hass' avocado fruit were heated with dry (50% RH) or moist (95% RH) forced air at 38Cfor 6 h and then stored at 5C and 85% RHfor up to 8 weeks. Fruit were evaluated weekly for quality and for the content of three triglycerides and three tocopherols. Heated fruit had higher weight loss. The nonheated fruit and those heated with dry air displayed the best external quality. Fruit heated with dry air exhibited the best internal quality and the lowest chilling injury incidence. The respiration rate was more intense in fruit heated with moist air. Fruit firmness immediately after harvest was 51N, but decreased to less than 20 N at the end of the storage period in the three treatments. The analysis of triglycerides and tocopherols showed that the 1,2-Dilinoleil-3-Oleil-Glycerol and ,-tocopherol were the most abundant compounds. Therefore, postharvest treatment with dry forced hot air before storage or transport reduces the incidence of chilling injury, and decreases quality deterioration in ,Hass' avocado fruit. [source] Effects of Mild Heat Treatment on Microbial Growth and Product Quality of Packaged Fresh-Cut Table GrapesJOURNAL OF FOOD SCIENCE, Issue 8 2007L. Kou ABSTRACT:, The changes in packaged fresh-cut grape quality and microbial growth as affected by mild heat treatments and the retention of grape cap stems during 5 °C storage were evaluated. Each individual grape was either manually pulled off (stemless) from the stems, or cut (cut stem) to allow for a 1- to 2-mm cap stem remaining on the berry. The samples were sanitized in 100 mg/L chlorine solution for 1 min, followed by a mild heat treatment in a water bath (45 °C, 8 min) or an oven (55 °C, 5 min). After cooling, the berries were packaged in rigid trays sealed with a gas permeable film and stored at 5 °C. Product quality and decay rate were evaluated periodically during storage. The results indicate that in the package headspace for hot water treatment of stemless grapes, partial pressures of O2 declined significantly (P < 0.05) less and C2H4 increased significantly (P < 0.001) less than for the control and hot air treatment. Stem removal and heat treatment had significant (P < 0.05) effects on the decay rate of grapes during storage. Hot water treatment maintained a significantly lower decay rate than the control and hot air treatment throughout the entire storage. Color and texture were not significantly (P > 0.05) affected by either heat treatment or stem removal. Grapes that retained the cap stems and received hot water treatment had the lowest decay rate and lowest microbial growth with the absence of any negative impact on grape color, texture, and flavor. [source] Hot air treatment decreases chlorophyll catabolism during postharvest senescence of broccoli (Brassica oleracea L. var. italica) headsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2006Maria L Costa Abstract A hot air treatment was applied to broccoli (Brassica oleracea L. var. italica) florets and its effect on chlorophyll catabolism during postharvest senescence was analyzed. Florets were treated at 48 °C for 3 h and then placed in darkness at 20 °C. During storage, the yellowing of florets occurred simultaneously with a decrease in chlorophylls and an increase in pheophytins. Heat treatment delayed the appearance of yellowing by 2,3 days and a similar extension of shelf-life could be inferred. Also, the treatment delayed the onset of chlorophyll catabolism and slowed both the rate of chlorophyll a degradation and pheophytin accumulation. No effect on chlorophyll b degradation was found. Chlorophyllase and Mg-dechelatase activities increased from the first day of storage in untreated florets, whereas peroxidase-linked chlorophyll bleaching activity increased from day 3. In heat-treated florets, chlorophyllase activity did not increase until day 2 and then increased at lower rate than in controls. Mg-dechelatase and peroxidase-linked chlorophyll bleaching activities were similar in treated and control florets during the first 2 days of storage, but thereafter the activity of both enzymes was lower in heat-treated samples. In conclusion, a treatment at 48 °C for 3 h delayed chlorophyll a catabolism in broccoli during postharvest senescence and decreased the activities of chlorophyllase, Mg-dechelatase and peroxidase, three of the enzymes probably involved in chlorophyll degradation in plants. Copyright © 2006 Society of Chemical Industry [source] Effect of hot air treatments on senescence and quality parameters of harvested broccoli (Brassica oleracea L var Italica) headsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2005María L Costa Abstract Treatments with hot air were applied to broccoli (Brassica oleracea L) florets to investigate the effect on several quality and senescence parameters. To select the optimum treatment, florets were treated with different combinations of time/temperature ranging from 1 to 3 h and 37 to 50 °C and then placed in darkness at 20 °C. Most treatments delayed yellowing and loss of chlorophylls, except those performed at 37 °C, which accelerated senescence. Treatment at 48 °C for 3 h caused the highest delay in chlorophyll loss and was chosen to analyse its effect on quality and senescence. Non-treated florets showed yellowing and reduced their chlorophyll content during storage. Heat treatment delayed the onset of chlorophyll catabolism by 1 day and slowed down the rate of degradation. Treated florets also showed lower losses of total sugars and proteins and an inhibition of protein solubilisation. Control heads showed an increment in CO2 production, which was not detected in heat-treated florets. Total antioxidants decreased and thiobarbituric acid-reactive substances (TBARS) increased during storage. The treatment delayed the decrease in antioxidant content and inhibited the increment in TBARS. In conclusion, treatment at 48 °C for 3 h delayed broccoli senescence at 20 °C and contributed to maintaining an overall better quality of the product. Copyright © 2005 Society of Chemical Industry [source] | ||||||||||