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To measure the molecular parameters of Persian gum (PG) (gathered from Kazeroon plains/Iran) by gel permeation chromatography-multiangle laser light scattering (GPC-MALLS), water-insoluble part of gum was removed using filtration method. In the following, acidification of whey protein isolate/PG mixture solutions (pH 7.00-2.00) at different biopolymer mixing ratio (r 5 0.1-10) was induced by HCl, allowing turbidity, zeta potential and precipitation yield determinations. Contrary to previous studies, it was demonstrated that more than 93% of gum is composed of large water-insoluble particles and water-soluble part contains heavy and heterogeneous compounds with high weight-average molecular mass (up to 5.11 3 10 6 g/mol) and high dispersity index (2.54-6.64). Acid titration of the mixtures displayed that the net neutrality shifts to the higher pHs by increasing the mixing ratio, and the charge neutralization occurs at pHs near pH opt as well. Generally, the maximum interaction was found for a 1:1 WPI/PG mixture with the highest liquid precipitate yield achieved at pH 3.4. PRACTICAL APPLICATIONPersian gum exudes from the wild almond tree (Amygdalus scoparia), growing in the Middle East countries. The characteristics of this hydrocolloid highly depend on the color of exudate and region of the tree. As a mixture with gum Arabic, it has wide industrial and pharmaceutical applications due to economic reasons and high functionality. However, very few scientific information about this gum has been already published. Some researchers have displayed the emulsifier, stabilizer and fat replacer ability of this gum. The interaction of PG with other biopolymers such as proteins would be beneficial in food and pharmaceutical applications in the form of gels, microcapsules, etc. In this study, we have measured the watersoluble and insoluble fractions and molecular parameters of PG gathered from Kazeroon plains. To have a basic knowledge for our future investigations on encapsulation ability of PG-WPI complexes, titration method was applied for different PG-WPI admixtures.

The main objectives of this study were to measure molecular parameters of gum tragacanth by GPC-MALLS system and investigate the complexation behaviour of whey protein isolate/gum tragacanth mixed dispersions (0.5 wt% total biopolymer concentration) as a function of pH (7.00-2.00) and the biopolymer mixing ratio (r = 0.1-10) using spectrophotometric, zeta potential and precipitate yield determination methods. GPC-MALLS revealed that gum tragacanth contains relatively heterogeneous particles with high weight-average and number-average (M w = 7.74 9 10 5 g mol À1 and M n = 3.87 9 10 5 g mol À1 ) molecular mass and high dispersity index (~2.04 AE 0.3). Results of complexation displayed that as the biopolymer mixing ratio increases, the net neutrality shifts to the higher pHs. The critical values associated with the complex structure formation were found at r = 2 in which the charge density of the mixture was near zero at a wide range of pH (3.0-4.0). However, the highest precipitate yield achieved in pH 3.4.International Journal of Food Science and Technology 2016 WPI and gum tragacanth complex formation N. Raoufi et al.

Water and polyglycerol polyricinoleate (PGPR) contents were varied to investigate the effects of these parameters on the textural properties, surface color, and sensory qualities of compound chocolates. The content levels of water and PGPR were manipulated between 3–10 and 0.3–3.3%, respectively (content expressed as % by weight of finished product). Simultaneous variations in water and PGPR levels, especially in high ratios, resulted in a drastic reduction in the hardness values (p<0.001), darker color (p<0.01), and an unusual taste (p<0.05) but the effect of water addition was more pronounced than PGPR. It was observed that compound chocolates with 3% water content were not dissimilar from the control with respect to all properties. In the samples of the same water content, the effect of PGPR addition was nearly insignificant. For these confectionaries, the best proportion of ingredients for producing water‐containing compound chocolate was considered the one which has the least negative effects on bloom surface area and the texture.Practical applications: Manufacturing water‐containing imitation chocolates represent a general approach for adding all water‐base materials to chocolate such as cream, yogurt, milk, etc. or water‐soluble substances like trace elements and vitamins. Conventional chocolates become soft at above 28°C, and lose shape retention at above 32°C. Water addition provides a heat‐resistance compound chocolate with shape retention at a temperature above 40°C, being not sticky to the direct touch. However, there has been very limited information about water addition's effects on the chocolate structure. In order to be able to predict the structural variations, it is important to study how water affects the physical properties of the chocolates.

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