Effect of the re-use of the osmotic solution on the stability of osmodehydro-refrigerated grapefruit

Osmotic dehydration (OD) of grapefruit (55 degrees Brix sucrose solution, 30 degrees C) was carried out to obtain 75 g water/100 g sample in the final product. Although the grapefruit was replaced each time, the osmotic solution (OS) was reused for five OD cycles, with or without pasteurization. The samples obtained in cycles 1, 3 and 5, were stored at 10 degrees C. Changes in degrees Brix, water content, water activity, pH, total acidity, ascorbic acid content, cation concentration, respiration rate and total microbial counts at different storage times were analyzed and compared to fresh-cut grapefruit stored under the same conditions. During OD, a partial loss of the natural soluble substances present in the fruit was observed. In terms of the dehydration level reached by the fruit, it is possible to reuse the OS in up to 5 OD, without any reconcentration treatment. Nevertheless, it is advisable to pasteurize the OS before each cycle in order to obtain a product with a shelf-life of between 7 and 12 days in refrigeration, depending on the number of cyclesThe authors thank the Ministerio de Ciencia y Tecnologia and the Fondo Europeo de Desarrollo Regional (FEDER) for the financial support throughout the project AGL2005-05994.Moraga Ballesteros, MJ.; Moraga Ballesteros, G.; Martínez Navarrete, N. (2011). Effect of the re-use of the osmotic solution on the stability of osmodehydro-refrigerated grapefruit. Food Science and Technology. 44(1):35-41. https://doi.org/10.1016/j.lwt.2010.05.018S354144

Modelling the Effect of Temperature on Respiration Rate of Fresh Cut Papaya (Carica papaya L.) Fruits.

A respiration rate (RR) model based on Peleg’s equation was developed for predicting RRs of fresh cut papaya. Respiration data for fresh cut papaya at 3/4 maturity were generated at temperatures 5, 10, 15, 20, 25 and 30°C using a closed system. RRs was found to be significantly influenced by storage temperature and increased from 0.021 to 0.289 mL[O2]/kg·h and 0.063 to 0.393 mL[CO2]/kg·h as a function of O2 and CO2 gas concentrations, respectively. Peleg’s constant K 1 and K 2 were obtained from linear regression analysis using GraphPad Prism 5.0 software and regression coefficients have good fit with values close to unity. The model was verified to assess the capability of its predictability of the RRs over the temperatures. There was good agreement with the experimentally estimated RRs. Information derived from the model can contribute in the design of successful modified atmospheric systems for storage of fresh cut papaya

Modified atmosphere packaging confers additional chilling tolerance on ethylene-inhibited cantaloupe Charentais melon fruit

Cantaloupe Charentais melon fruits are subject to chilling injury when stored at low temperatures, around 2 °C. Ethylene-suppressed cantaloupe Charentais melon, expressing a 1-aminocyclopropane-1-carboxylic acid (ACC)-oxidase gene in antisense orientation, showed strong, but not total, resistance to chilling injury, allowing an extended storage at low temperatures. Modified atmosphere packaging (MAP) is known to alleviate chilling injury symptoms in a variety of chilling-sensitive horticultural commodities. In the present work, we have compared the effects of MAP in non-retractile plastic film and storage in air on ethylene production, respiratory activity, development of chilling injury symptoms, water loss, ion leakage and accumulation of ethanol and acetaldehyde in wild-type and ethylene-suppressed melons, during storage at 2 °C and after re-warming at 22 °C. MAP reduced chilling injury and extended the postharvest life of wild-type fruit and conferred additional chilling resistance on ethylene-suppressed melons. Reduction of ethylene production and water loss are necessary to prevent chilling injury symptoms in melon