Browning and Ascorbic Acid Degradation in Meals Ready-to-Eat Pear Rations in Accelerated Shelf Life

Abstract

Pears in syrup in flexible pouches are part of the U.S. Army's Meals Ready-to-Eat rations, which are expected to have a shelf life of 3 years at 26.7C. However, browning during storage was reducing the shelf life. Pear pouches were subjected to complete headspace removal and rotation during retorting for extended shelf life of 45 days at 48.9C. The pears were tested for browning, ascorbic acid and headspace composition during storage. A combination of complete headspace removal and rotation of pouches during retorting increased the acceptability of pear by decreasing ascorbic acid degradation and browning. Aerobic and anaerobic ascorbic acid degradation reactions took place in the pears, with most of the aerobic degradation beginning during retorting. A lag period of several days between different stages of ascorbic acid degradation was detected. Finally, the ascorbic acid loss followed zero-order kinetics, with a reaction rate dependent on the initial concentration. PRACTICAL APPLICATIONSThis paper highlights the importance of minimizing the headspace volume during vacuum packaging and enhancing the application of heat transfer during retorting to improve the preservation of color of thermally processed pears in flexible pouches. This process also serves to reduce the ascorbic acid degradation during storage.

Barriers and Chemistry in a Bottle: Mechanisms in Today’s Oxygen Barriers for Tomorrow’s Materials

“…It can react with reactive oxygen species (photo-initiated or heat-initiated in packaging processing) via two one-electron exchanges to dehydroascorbic acid (DHA) with monodehydroascorbic acid as the intermediate in an easily reversible reaction. Depending on the radical count in the matrix, the flexibility of the stabilized intermediate radical structure can provide either an antioxidative, quenching other radicals by forming DHA, or a prooxidative nature, abstracting hydrogen from non-radical organics and forming L-AA [141][142][143]. Instead of reverting back to L-AA, DHA can also undergo a hydrolysis reaction, forming 2,3-diketogulonic acid through ring cleavage.…”

Improving color preservation of diced peaches in flexible retortable pouches

“…Although retort pouches solved some of the problems associated with soldier's rations, stability of food products remains a challenge for food scientists, especially when refrigeration is not available. In the case of wet pack fruits for MRE rations, the U.S. Army stipulates a shelf life of 6 months at 37.8°C and 36 months at 26.7°C (Maldonado et al, 2015).…”

Multifactors accelerated aging of sterilized acidic pudding determined by traditional and fluorescence techniques

“…Several factors have been applied to determine the quality of shelf‐stable food such as: oxygen pressure to sterilized potatoes and roasted or ground coffee (Cardelli & Labuza, ; Dole & Perrin, ), light to milk protein concentrate powder and pasteurized milk (Intawiwat et al, ; Semagoto et al, ), and high temperature (up to 50 °C) to human milk replacement formula, UHT milk, and fruit‐filled snack bars (Corrigan et al, ; Curia & Hough, ; Grewal et al, ). To accelerate aging, the effect of other parameters were investigated such as: oxido‐reduction potential of orange juice (Fustier, St‐Germain, Lamarche, & Mondor, ), headspace atmosphere in rapeseed oil (Kozak & Samotyja, ), headspace volume in retort pouches containing pears in syrup (Maldonado et al, ), relative humidity of dried coconut powder (Jena & Das, ), and pH of sweet whey powder (Dattatreya, Etzel, & Rankin, ).…”