MICROSTRUCTURE AND TEXTURE OF PANELA TYPE CHEESE-LIKE PRODUCTS: USE OF LOW METHOXYL PECTIN AND CANOLA OIL AS MILK-FAT SUBSTITUTES

Abstract

Three Panela type white fresh cheese-like products (PCLP) were prepared using skim milk incorporated with 6.8 g L- 1 of emulsified canola oil (CO) and different concentrations of low methoxyl pectin (P): 0, 1.25 and 2.5 g L-1. In addition, full-milk fat (FFC) and low-milk fat (LFC) Panela type cheeses were manufactured from milk containing 27 and 6.8 g L-1 of milk-fat (MF), respectively. After 72 h of storage (4 ºC), the cheese systems were subjected to proximal chemical analysis, instrumental texture determination and microstructure observation using Scanning Electron Microscopy. The cheese systems showed differences in their chemical composition, structural arrangement and textural characteristics, due to chemical composition variation of the milk from which they were elaborated. Complete substitution of MF by emulsified CO, resulted in cheese-like products having a highly porous protein network, interrupted by numerous small drops of oil. P contributed to the openness of the protein network of the cheese-like products conferring it the ability to retain greater initial amounts of whey in comparison with those retained into the protein network of the FFC. Polynomial models that estimated the textural characteristics of the cheese systems as a function of P, CO and MF concentrations in the milk used to prepare them. Increases in the concentration of P, CO and MF were related with lower values of hardness and chewiness, whilst lower springiness values in the cheese systems were associated with increasing of the P and MF concentrations. The cohesiveness of the cheese systems was negatively affected by CO.