59th Annual Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 59th annual meeting of the Rocky Mountain Conference on Magnetic Resonance, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in Snowbird, Utah, July 22-27, 2018

Production of Calcium Reduced Micellar Casein Concentrate Powders and Their Use in Process Cheese Products

Protein is an essential dietary component, and sufficient intake is vital in a healthy and balanced diet. Consumers are becoming increasingly aware of and knowledgeable about the role of protein in the diet. Two of the next-generation dairy protein ingredients isolated from milk are micellar casein (MCC) and milk-derived whey protein, isolated from skim milk using microfiltration (MF). Membrane filtration has been used extensively by the dairy industry to produce a variety of dairy ingredients from milk. MCC manufactured from freshly pasteurized milk can be directly consumed or as a supplement to fortify and enhance nutritional qualities in processed food products. However, the use of MCC as an ingredient in food applications is sometimes limited due to some of its poor functional properties. Therefore, several researchers studied different ways to improve the functionality of the MCC. One of them is the acidification of milk to solubilize colloidal calcium. The first objective of this study was to develop a novel filtration method to manufacture MCC with higher soluble casein factions while effectively removing the calcium from acidified skim milk. Although some of the previous studies achieved a 50% reduction in calcium, there might be a loss of soluble caseins through MF permeate when MF-DF is directly applied to acidified skim milk. In addition, acidification of milk with any acid salts is nonreversible, whereas acidification of milk with CO2 is reversible. Hence an alternate strategy for improving casein functional properties via shifts in protein and mineral distributions is manufacturing modified milk protein ingredients by acidifying the milk through CO2 injection, giving a clean label functional MCC. In this study, we have evaluated the novel process of producing calcium reduced micellar casein concentrate powders (RC-MCC) using MF, UF-DF, and injecting the CO2 into the liquid Micellar casein to lower the pH to 5.7 and maintain the same pH during the UF-DF process. This novel production process resulted in an RC-MCC with 30% less calcium than the C-MCC, retaining higher soluble casein fractions; otherwise, it would have permeated through the MF when only MF is used to produce MCC powders. Furthermore, the retention of serum casein in the resultant RC-MCCs was established quantitively by comparing the ζ-potential and particle size distribution values of RC-MCC and C-MCC powders. We conclude that an additional UF-DF and CO2 injection step to the current standard only MF process could produce reduced calcium MCCs without losing a lot of serum casein fractions generating because of pH adjustment to solubilize calcium. The objective of the second study was to evaluate the physicochemical and functional properties of 30% reduced calcium MCCs (RCMCC) produced in the first study to confirm improved functionality of RCMCC powders with higher soluble caseins lower calcium content. This study evaluated the pilot-scale production of calcium-reduced MCC 80 powders using a novel Microfiltration-CO2 injection-Ultrafiltration process and the effect of the calcium reduction on the physicochemical and functional properties of the RC-MCC powders and dispersions, respectively. In addition, control micellular casein powders (C-MCC) without CO2 injection were also compared with RC-MCC. This study confirmed significantly improved instant solubility and heat stability of the RC-MCC powders. In addition, reducing calcium was observed to improve foam capacity; however, the emulsions stability and foam stability were lower than control powder dispersions. This could be attributed to smaller particle size and not enough viscosity to retard the coalescence of smaller oil droplets or foam bubbles. The objective of the third study was to determine if a process cheese product (PCP) could be produced with less emulsifying salts if 30% reduced calcium RCMCC is utilized in the formulation and its impact on the functional properties of PCP. PCP formula made with reduced calcium MCC at 25% less emulsifying salt than control PCP had improved the functional characteristics. Using reduced calcium MCC, PCP manufactured with 25% less emulsifying salts showed a significant decrease in hardness, improved meltability, and optimal viscosity, confirming improved emulsification in the process cheese products. Consequently, this study concluded a 30% reduced calcium MCC powder could be used to partially replace emulsifying salt up to 25% in PCP manufacture

Investigation of Sugar/Polyols as Weakly Interacting Cosolvents and their Influence on Hardening of High-Protein Nutrition Bars

High-protein nutrition (HPN) bars (≥ 30% protein) have limited shelf life and become excessively hard during storage. Various mechanisms have been proposed to explain the hardening. The objectives of this research were to investigate the chemistry of HPN bar hardening and propose solutions for slowing it and improving bar texture. In phase 1, HPN bars were made containing 34% whey protein isolate (WPI) or milk protein concentrate (MPC) powder, along with either sorbitol syrup or glycerol, and vegetable shortening or cocoa butter. Substituting MPC for WPI made the bars brittle and crumbly. Using glycerol initially made bars softer but accelerated hardening. Cocoa butter increased bar hardness because of its higher solid to liquid content. Most water (~99%) in HPN bars made using sorbitol syrup is present as bound water, with ~0.9% as intermediate water and ~0.1% as bulk water. During storage bound water increased ~0.02 g/100 g of solids while intermediate water decreased, suggesting changes in state of water taking place at protein surfaces. During storage, there were changes in protein conformation indicated by an increase (~4°C) in heat denaturation temperature of β-lactoglobulin and α-lactalbumin and a 15 to 40% decrease in denaturation enthalpy. In phase 2, various bar formulations were tested involving different proportions of proteins, lactose, glycerol, and sorbitol syrup, as well as type of lipid component, and disulfide bonds inhibition. Decreases in bar hardening occurred when MPC and WPI and sorbitol syrup and glycerol were used in combination. In phase 3, HPN bars made with 38% protein powder as a 50:50 combinations of WPI and MPC and with 20% of sorbitol syrup substituted with glycerol, had good texture and minimal hardening during storage. Bar hardening was not caused by phase separation of protein and sorbitol, Maillard browning, or formation of inter-molecular disulfide bonds. Minimizing bar hardening requires prevention of entropy-induced protein aggregation by masking hydrophobic regions on protein surfaces and preventing formation of extended protein networks. It is proposed that preferential exclusion of cosolvents causes glycerol to be oriented at protein surfaces such that its carbon backbone masks hydrophobic regions thus avoiding a decrease in entropy of water molecules. (229 pages

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