Ascorbic acid retention, microbial growth, and sensory acceptability of lettuce leaves subjected to mild heat shocks

• Published in: Journal of food science Vol. 71; no. 2; pp. S188 - S192
• Main Authors: Moreira, M. del R, Ponce, A.G, Valle, C.E. del, Roura, S.I
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.03.2006; Institute of Food Technologists
• Subjects: ascorbic acid; bacteria; bacterial contamination; Biological and medical sciences; cold storage; color; enzymatic browning; enzyme activity; food contamination; Food industries; food quality; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; heat shock treatments; heat stress; hot water treatment; Lactuca sativa var. crispa; leaf lettuce; lettuce; mesophilic bacteria-sensory attributes; microbial growth; minimally processed foods; sensory properties; storage quality; temperature; texture; Microorganism growth; Heat treatment; Vegetables; Ascorbic acid; Vitamin; heat shock treatments; Plant leaf; mesophilic bacteria-sensory attributes; Retention; Heat; Lettuce; Plant part; Bacteria
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/j.1365-2621.2006.tb08924.x

Heat shocks not only produced a reduction in the initial content of ascorbic acid but also affected the rate of degradation of ascorbic acid during refrigerated storage. Samples treated at higher temperatures presented faster rates of degradation. The heat shocks produced an initial reduction in the counts of mesophilic aerobic microorganisms, with greater reductions associated with the higher shock temperatures. However, high shock temperatures promoted faster microbial growths during storage, probably due to the liberation of nutrients by the disruption of membrane barriers. The sensory attributes of lettuce leaves subjected to heat shocks presented mixed results. Thermal treatments affected the enzymatic activity, reducing browning phenomena, but also caused deleterious effects on surface color and texture of lettuce leaves. Heat shocks of 50 degrees C could be useful for short-term preservation of minimally processed lettuce, where the high rate of metabolic processes cause great deterioration of fresh products.