| Título: | Solubilized micellar calcium induced low methoxyl-pectin aggregation during milk acidification |
| Autores: | HARTE, FEDERICO ; MONTES, C. ; ADAMS, M. ; SAN MARTIN-GONZALEZ, M. F. |
| Tipo de documento: | texto impreso |
| ISBN/ISSN/DL: | 41460 |
| Nota general: | ISBN: |
| Langues: | Inglés |
| Clasificación: | |
| Resumen: | Low methoxyl (LM) pectin was combined with 3-kDa molecular weight cut-off permeates from milk subjected to pH 6.7 to 5 and 7ºC or 40ºC with the objective of studying the effect of solubilized micellar calcium on viscoelastic properties of LM-pectin-milk mixes. Lowering the pH of skim milk with hydrochloric acid during ultrafiltration gradually promoted permeates to exhibit gel-like behavior when combined with LM-pectin. The onset of the gel-like behavior (G' > 1) occurred at a higher pH when permeates were obtained from milk filtered at 7ºC compared with 40ºC. As pH value during ultrafiltration approached 5 and regardless of temperature, G' for permeate-pectin mixes approached the same values (~70 Pa) as G' for skim milk-pectin mixes. In all cases G' was highly correlated with free calcium concentration (r > 0.95). The gradual acidification of skim milk-LM-pectin using glucono lactone, promoted a sharp increase in storage modulus as pH approached 5.2 and a maximum G' increment (AG') at pH ~4.9. From pH 4.9 to 4, G' continued to increase but at smaller increments. It was concluded that LM-pectin-casein micelle interaction in milk is a 2-step process: 1) solubilized micellar calcium dependent pectin-pectin interaction as pH approaches 5.0 to 4.9, and 2) pectin¨C casein micelle interaction in the 5.0-4.9 to 4.0 pH range. Key words: casein micelle, pectin, calcium, milk. |
| Nota de contenido: | En: Journal of Dairy Science. -- (90) : 2705-2709 (2007) |
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