No abstract

Date fruits vary widely in the hardness of their edible parts and they are classified accordingly into soft, semi-dry, and dry varieties. Fruit texture, a significant parameter in determining consumer acceptance, is related to the tissue structure and chemical composition of the fruit, mainly the ratio of sucrose to reducing sugars. This study aimed to understand the relationship between the chemical composition, microstructure, and texture profile of 10 major Emirati date fruits. The soluble sugars, glucose and fructose, represent ca 80 g/100 g of the fruits on the basis of dry weight (DW) while the dietary fiber contents varied 5.2–7.4 g/100 dg D.W. with lignin being the main determinant of the variability. The textures of the samples were studied using instrumental texture profile analysis. While no correlation was found between the soluble sugar and texture parameters in this study, the different fiber constituents correlated variably with the different parameters of date fruit texture. Lignin, arabinoxylan, galactomannan, and pectin were found to correlate significantly with fruit hardness and the related parameters, gumminess and chewiness. Both lignin and arabinoxylan correlated with resilience, and arabinoxylan exhibited a strong correlation with cohesiveness.

The aim of this study is to evaluate the effect of fortification of camel milk (CM) and bovine milk (BM) with 1-4% of bovine casein (CN) and/or whey protein (WP) on the quality of yoghurts after 12 hours of fermentation. Response surface methodology was used to design the experiment. Yoghurts were evaluated for pH, acidity, hardness and rheology.  The results revealed that addition of WP and CN significantly improved the hardness (p<0.000), and the rheological properties; storage modulus (G’, p<0.005), and loss modulus (G”, p<0.005), viscosity (p<0.005) and tan δ (G’’/G’, p<0.05) of CM yoghurts. Both types of yoghurts attained highest viscosity, G’ and G” values at highest level of WP (4%) and intermediate level of CN (2.5%) while increased CN ratio showed negative effects on yoghurts rheology. It can be concluded that the amount of total proteins as well as altering CN-to-WP ratio are important for the formation of strong gel network and the production of good  quality set yoghurts.

No abstract

This study evaluated the effects of added casein (CN), whey proteins (WPs), calcium chloride (CaCl 2), and a hydrocolloid [gum arabic (GA), gelatin (GL), sodium alginate (ALG), or pectin (PC)] on the quality of camel milk yogurts. Maximum viscosity was achieved with 4% WP and 2% CN. Addition of CaCl 2 , GA, and GL negatively affected the viscosity/rheology of WP/CN-fortified yogurts while ALG and PC had positive effects. Syneresis was highest in yogurts containing WP/CN and was reduced with the addition of hydrocolloids in the order GA