Plastics containing castor oil exhibited
improved tensile strength and Young's modulus and storage
modulus under high humidity (75% RH), compared with neat
glycerol plasticized protein plastics (Tian et al., 2012). Similar results
were found while incorporating cinnamon or ginger essential
oils into soy protein matrix (Atares et al., 2010). Ginger oil made the
films less resistant to elongation and less stretchable although
lipideprotein interactions led to more resistant and stretchable
films in the case of cinnamon oil. Effects of the ratio of oleic acid to
stearic acid and ultrasonic/microwave assisted treatment on the
water vapor permeability (WVP) and contact angle of soy protein
isolate films showed that the prepared films (oleic acid: stearic
acid ¼ 2:3) had the lowest WVP value (0.1 1012 g cm1 s1 Pa1)
and highest contact angle value (135).