Application of a digital image procedure to evaluate microstructure of caseinate and soy protein acid gels

INGRASSIA, ROMINA; COSTA, JUAN PABLO; HIDALGO MARÍA EUGENIA; MANCILLA CANALES, MANUEL; CASTELLINI, HORACIO; RIQUELME, BIBIANA; RISSO, PATRICIA

LEBENSMITTEL-WISSENSCHAFT UND-TECHNOLOGIE-FOOD SCIENCE AND TECHNOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2013 vol. 53 p. 120 - 127

0023-6438

Q1 según Scimago a la fecha de publicaciónAcid gelation of proteins is commonly used in the food industry and itcan be induced by the addition of glucono-delta-lactone (GDL). The aim of this work was to usetextural analysis of images in order to assess possible changes in themicrostructure of bovine sodium caseinate (NaCAS) and soy protein isolate (SPI)acid gels. Thegelation rate of NaCAS relatedto the amount of GDL was evaluated. Also, the effectof the presence of NaCAS hydrolyzates obtained at different hydrolysis timesby the enzyme of Bacillus sp. P7 was studied. Finally, SPI acid gelswere evaluated in the presence of whey soy protein isolate (WSP) in different ratios.The gel images were obtained by conventional optical microscopy and texture parameters were obtained by using specificprograms which were developed in Python language. Shannon entropy, smoothness, mean normalized grey levelvariance and uniformity were analyzed as estimators of the texture of theimages obtained. Results obtained in theevaluated systems showed that these parameters were able to represent the structuralchanges in the gel network, as changes in size of pores orin degree of compactness. Also, these results were contrasted with rheologicalproperties of the systems evaluated.