Heat-Induced Whey Protein Gels: Effects of pH and the Addition of Sodium Caseinate

Autor(es)

Picone, Carolina S. F. ^[1] ; Takeuchi, Katiuchia P. ^[2] ; Cunha, Rosiane L. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Campinas UNICAMP, Fac Food Engn, Dept Food Engn, BR-13083862 Campinas, SP - Brazil

^[2] Univ Goias, Sch Agron, Dept Food Technol, BR-74001970 Goiania, Go - Brazil

• Tipo de documento: Artigo Científico
• Fonte: FOOD BIOPHYSICS; v. 6, n. 1, p. 77-83, MAR 2011.
• Citações Web of Science: 8

Resumo

The effects of pH (6.7 or 5.8), protein concentration and the heat treatment conditions (70 or 90 A degrees C) on the physical properties of heat-induced milk protein gels were studied using uniaxial compression, scanning electron microscopy, differential scanning calorimetry, and water-holding capacity measurements. The systems were formed from whey protein isolate (10-15% w/v) with (5% w/v) or without the addition of caseinate. The reduction in pH from 6.7 to 5.8 increased the denaturation temperature of the whey proteins, which directly affected the gel structure and mechanical properties. Due to this increase in the denaturation temperature of the beta-lactoglobulin and alpha-lactalbumin, a heat treatment of 70 A degrees C/30 min did not provide sufficient protein unfolding to form self-supporting gels. However, the presence of 5% (w/v) sodium caseinate decreased the whey protein thermo stability and was essential for the formation of self-supporting gels at pH 6.7 with heat treatment at 70 A degrees C/30 min. The gels formed at pH 6.7 showed a fine-stranded structure, with great rigidity and deformability as compared to those formed at pH 5.8. The latter had a particulate structure and exuded water, which did not occur with the gels formed at pH 6.7. The addition of sodium caseinate led to less porous networks with increased gel deformability and strength but decreased water exudation. The same tendencies were observed with increasing whey protein concentration. (AU)

• Processo FAPESP: 03/08119-5 - Influência do tratamento térmico e acidificação nas propriedades reológicas de géis de proteínas do leite
• Beneficiário: Carolina Siqueira Franco Picone
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica