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Effect of pullulan concentration and pH on the interactions between whey protein concentrate and pullulan during gelation
Author(s) -
Zhang Minghao,
Sun Haiyue,
Liu Yankai,
Wang Yu,
Piao Chunhong,
Cai Dan,
Wang Yuhua,
Liu Jingsheng
Publication year - 2020
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.10678
Subject(s) - pullulan , chemistry , whey protein , hydrogen bond , hydrophobic effect , rheology , zeta potential , disulfide bond , chromatography , fourier transform infrared spectroscopy , polysaccharide , chemical engineering , organic chemistry , biochemistry , molecule , materials science , nanoparticle , engineering , composite material
Abstract BACKGROUND Whey protein concentrate (WPC)/pullulan (PUL) hydrogel is applied as a microencapsulation wall material to protect probiotics. However, the interactions between WPC and PUL during gelation have not been clarified. In the present study, the effects of PUL concentration and pH on the interactions between WPC and PUL during gelation were evaluated with respect to appearance, zeta‐potential, sulfhydryl group amount, surface hydrophobicity and infrared spectroscopy measurements. The rheological properties of WPC/PUL gels were also determined. RESULTS The results obtained showed that a proper concentration (0.40 g mL –1 ) of PUL could improve the gel by enhancing the strength of hydrogen bonding, electrostatic interactions and exposure of hydrophobic groups, whereas too much PUL inhibited the formation of disulfide bonds. Furthermore, hydrophobic interactions, disulfide bonds and hydrogen bonds were destroyed in varying degrees under an alkaline environment. The rheological results also demonstrated a similar effect of PUL concentration and pH on the storage modulus ( G ') of WPC/PUL gels. CONCLUSION When the WPC/PUL gel was formed at PUL concentration of 0.40 g mL –1 and pH 7.0, the interaction between WPC and PUL could be enhanced, which is beneficial for the future application of WPC/PUL gels in the food industry. © 2020 Society of Chemical Industry