44F-4 |
Effect of edible whey protein coatings on the quality of stored shelled pecans |
V. SANTANA1, G. I. Olivas-Orozco1, and F. R. Del Valle2. (1) Facultad de Ciencias Químicas, Univ. Autónoma de Chihuahua, Ciudad Universitaria, Chihuahua, Mexico, (2) Dept. of Chemical Engineering, New Mexico State Univ., PO Box 30001, MSC 3805, Las Cruces, NM 88003-8001 Pecans (Carya illinoensis) are an important agricultural commodity in northern Mexico, as well as in many parts of the United States. Due to strong consumer preference, the pecan industry has, in recent years, faced a continually increasing demand for the shelled products. However, this has created a serious problem due to the fact that shelled pecans possess a considerably shorter shelf life than do natural ones: the former are much more susceptible to oxidative rancidity than the latter. The purpose of this research, therefore, was to evaluate the use of edible whey protein isolate (WPS) coatings for shelled pecans as a means for delaying lipid rancidity and increasing shelf life. A two-level experimental design was utilized as follows: dipping solution compositions, 50% WPS/50% glycerol and 60% WPS/40% glycerol; number of immersions of shelled pecans in dipping solution, 2 and 3. An untreated sample served as control. All samples were stored at 37°C for 12 weeks, with weekly objective evaluations being carried out for changes in color(luminosity, red color intensity yellow color intensity), texture (cohesiveness, chewiness and hardness utilizing a Texture Technologies Model TAXT2 machine)and degree of rancidity (TBA test). Weekly sensory evaluations (flavor) were also conducted. Statistical analysis of the results revealed the following. All coatings effectively retarded oxidative rancidity (TBA test) as well as deteriorative changes in flavor, color and texture (p<0.05), verifying the fact that WPI/glycerol edible films do delay oxygen penetration. The 50%WPI/50% glycerol film with three dippings was found to be the best quality protector for shelled pecans (p<0.05). Finally, a very good correlaton (r2=0.895) was found between the objective (TBA test) and subjective flavor determinations.
Session 44F, Product Development
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