A Method for Determination of Unbound Fats in Protein Bar Formulations Compared with Isolated Fat/Protein Combinations to Optimize Shelf Life

Abstract

Abstract Objectives Protein bars form a growing part of the snack food industry, but shelf life is typically limited by bar hardening due to protein aggregation related to the migration of other nutrients. Addressing these issues will extend protein bar shelf life while continuing to maintain nutrient density for military personnel and extreme athletes. We developed a method to examine the interaction of fats and proteins in bars and in simple mixtures in order to address lipid/protein interaction and lipid migration. Methods Mixtures of dairy protein and fats were created in order to determine ideal fat/protein ratios. Fats tested were palm kernel oil (PKO), cocoa butter, coconut oil, and canola oil. Proteins included milk protein isolate, a dairy protein blend, whey protein concentrate, and two whey protein isolates (WPI). Fats were liquified, mixed with protein at 0/100 up to a 50/50 ratio by weight and allowed to solidify. Solidified pellets were suspended in filters placed in conical tubes at a temperature four degrees Celsius above the melting point of the fat for twelve to twenty-four hours. The weight of melted fat that passed through the filter was then determined. Results At 50/50 ratios, the combinations of cocoa butter and PKO with WPI and whey protein concentrates demonstrated 1% and 3% fat loss, respectively. While a ratio of 59/41% lipid/protein respectively, cocoa butter and PKO with WPI continue to have the lowest residual fat at 14% while the highest is coconut oil and milk protein isolate at a residual fat content of 29%. Low residual fat is between one and three % residual in a 50%/50% matrix, while low-fat retention is anything above 14% residual fat. The dairy blend and milk protein isolate have low-fat retention with saturated fats but have increased retention with canola oil. Coconut oil has a high residual fat of 25% with the milk protein isolate that contains both casein and whey proteins. Conclusions The ideal fat protein mixtures for military personnel and extreme athletes are WPI's and with PKO or cocoa butter. By using these two fats with the whey protein isolates, it creates an ideal matrix for protein bar stability preventing bar hardening and long shelf life while keeping nutrient density. Funding Sources Military grant-funded by the Defence Logistics Agency and SMRC.