Date of Award:

2000

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Nutrition, Dietetics, and Food Sciences

Department name when degree awarded

Nutrition and Food Sciences

Advisor/Chair:

Marie K. Walsh

Co-Advisor/Chair:

Charles E. Carpenter

Abstract

The effects of altering pH and calcium level during whey protein extrusion were assessed by measuring the protein solubility and WHC of the textured whey protein (TWP). TWP samples were produced by extruding dry mixtures of 2/3 WPC 80 (80% protein) and 1/3 cornstarch using screw speed of 200 rpms, feed rate of 23 g/min, water flow rate of 11 g/min, and product temperature of 150°C. The levels of acid and base were adjusted by adding concentrated HCl or NaOH, respectively, to the water source. Calcium was added to the raw mix in the form of calcium chloride dihydrate before extrusion at levels of 0.4%, 0.88%, and 1.69% calcium per protein (w/w). It was shown that WHC of TWP was increased (p < 0.05) by extrusion with water. WHC was further promoted by extruding with increased levels of base. Solubility of whey protein in water was reduced by extrusion, especially when extruded with added acid or calcium.

The practicality of using hydrated TWP in beef patties was determined using sensory, physical, and instrumental analysis. An open consumer panel was conducted on six beef patty samples: 1) 100% beef, 2) 30% TWP extruded with 0.2 M NaOH (TWP0.2MNaOH), 3) 30% TWP extruded with 1.69% calcium (w/w protein) added (TWP1.69%Ca2+), 4) 30% TWP extruded with water (TWPH2O) , 5) 30% TWP extruded with 0.1 M HCl (TWP0.1MHCl), and 6) 30% textured soy protein (TSP). It was found that patties containing 30% TWP0.2MNaoH were equal (p < 0.05) to 100% beef patties in tenderness, juiciness, texture, flavor, and overall acceptability, and well above the scores for patties with 30% TSP.

TWP0.2MNaoH was then tested by sensory, physical, and instrumental analysis at three usage levels, 30, 40, and 50%, against 100% beef patties. Patties with up to 40% TWP0.2MNaOH were well accepted (p < 0.05) by consumers, and had higher cook yield, less diameter reduction, and less change in thickness than 100% beef patties. These results suggest great potential for the use of textured whey protein as a meat extender.

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