Concentration and Production of Cryoprotective Additives from Agricultural Waste Streams and Abundant Protein Sources

Ice recrystallization is a major problem leading to a deterioration of quality of frozen food products and biomedical materials. Production of additives with ice recrystallization inhibition (IRI) activity could control ice crystal growth, limiting the freezing induced damage of these products. While IRI active molecules contain the ability to slow deterioration and maintain ability, their lack of mechanistic understanding, abundant source material, and economic feasibility has led to a limitation in their use. In our work we take a different approach to production of cryoprotective additives by targeting food grade abundant protein sources and agricultural byproducts to investigate new IRI active molecules, by using an abundant protein sources (soy protein isolate (SPI)), a readily produced byproduct (cheese whey), and an immerging ingredient for consumption of agricultural waste (black solider fly larvae (BSFL)). SPI was found to produce IRI active hydrolysates after complexation with soy lecithin by hydrophobic interactions and hydrogen bonding. This complexation resulted in the formation of fibril structures which did not bind to the ice crystal but disrupted the water system resulting in IRI activity. Glycomacropeptdie (GMP) was concentrated from cheese whey and exhibits potent IRI activity in low NaCl (10mM) and pH systems (3-4.5) and ice binding activity. GMP has limitations in high pH and salt systems demonstrating an importance in electrostatic interactions for activity but has immense potential in acidic systems. The BSFL was fractionation using Osborne fractionation and the albumin fraction contained immense IRI activity. After further fractionation with preparative liquid chromatography a polysaccharide in the BSFL was identified as having high IRI and ice binding activities regardless of NaCl concentration (10mM-200mM) or pH (3.0-9.0) making it a versatile IRI agent. A cuticle protein within the BSFL also demonstrated IRI activity indicating the polysaccharide and proteins in BSFL have immense cryoprotective potential. Hence this Dissertation contributes positively to the field of cryopreservation by identification of novel additives from more abundant and economically feasible sources.