49E-29 |
|
J. STOJANOVIC1, C. Kaewplang, L. Youkai, and J. L. Silva4. (1) Food Science and Technology, Mississippi State University, Box 9805, Mississippi State, MS 39762, (2) Dept. of Food Science & Technology, Mississippi State Univ., 205 Herzer Bldg., Campus Mailstop 9805, Mississippi State, MS 39762-9805 Fresh blueberries and those for the frozen market tend to contain a high microbial load, including yeasts and molds. Temperature abuse and time may influence the amount and activity of the native antioxidant compounds. This makes them very perishable and susceptible to rapid spoilage. The objective of this study was to evaluate different treatments and storage temperatures (refrigerated and abused-room temperature) on microbial load and quality of rabbiteye (Vaccinium ashei) blueberries. Fresh picked blueberries were packed untreated (control) or treated with 100ppm chlorine (CaHOCl) solution or TsunamiŽ (40 ppm peroxyacetic acid) for 30s, air dried and placed in plastic clamshells. Samples were stored at 2-3°C (RF) or at 21°C (RT), and evaluated every five days for up to 30 days. Samples were analyzed for texture, weight loss, color, total anthocyanins, total phenolics, yeast and molds, aerobic plate and psychotropic plate counts. Anthocyanins and phenolics were extracted using methanol with 4% acetic acid. Anthocyanins were determined using pH differential method and phenolics using Folin-Ciocalteu reagent. Color, texture and firmness changes were more prominent on RT berries. Different treatments did not influence texture of the RF berries. After 25 d, RT berries lost 24-36% of their total weight, while RF berries lost 10-15% of their weight after day 30. Total phenolics significantly increased from 472 to 629 mg/100g during 30 d in RF berries, while there were no changes in anthocyanins over time or by storage temperature. A 2-log increase in microbial counts was recorded for RT berries regardless of treatment after 5 days (end of acceptable quality). Chlorine solution was most efficient in reducing microbial counts on berries. Pretreatment will not aid in delaying spoilage of berries by temperature abuse. Refrigeration of blueberries seems to be more important than pretreatment in extending shelf-life and maintaining quality of blueberries.
Session 49E, Fruit & Vegetable Products: Fresh fruit
|