39B-25

Y. cao and S. CHANG. food and nutrition, north dakota state university, Fargo, ND 58105

(1) Whole soybean have shown the possibility to be used as a raw material for producing film by deposition of film forming solution. However, the strength of such film needs to be improved as compared to the films made from pure protein sources. The involvement of transglutaminase (TG) and film enhancers in film forming solution may yield stronger films in terms of tensile and puncture strengths. It is necessary to examine the feasibility of the use of TG reaction and film enhancers for improving the strength of the film (2) To characterize the physical properties of soy films by incorporating TG and carbohydrate and protein enhancers (3) Whole soybeans were ground into fine powder, which was then extracted with water. Soybean films were prepared from the soybean water extract by deposition of film forming solution. Various experiments, involving TG-catalyzed protein crosslinking and the addition of film enhancers (low and high methoxyl pectins, whey protein isolate (WPI) and soy protein isolate (SPI)), were performed before the extract was cast to form films. Physical characteristics such as tensile strength (TS), puncture strength (PS) were measured according to ASTM methods. (4) TG functioned with the need of a reducing agent such as 2-mercaptoethanol. The effects of pectins on TG treated films depended on the amount of pectins and type of pectin used for film production. TG treated film made with WPI had TS of 6.94 Mpa and PS of 2.00 Mpa, which were the highest values as compared to TG treated soy films made either with SPI, LM or HM pectin, respectively. (5) Transglutaminase could be a useful tool to enhance the strength of the soy films by crosslinking reaction between glutamine and lysyl residues of peptide chains. The effective utilization of transglutaminase could be further improved by incorporating film enhancers. Using whole soy instead of purified proteins as a starting raw material for film forming could reduce the cost of production.