Further applications for the heat shock puffing of food gels : a thesis presented in partial fulfilment of the requirement for the degree of Master of Food Technology in Food Processing at Massey University, Palmerston North, New Zealand
Factors governing the puffability of food gels were studied in detail. Some experiments were conducted and results discussed on the effects of soluble solids, changes of pH and pretreatment of food gels on their water holding capacity. The effects of the soluble solids, fat and fibrous texture on the thermoplasticity of food gels were also examined.
The application of a puffing technique was directed toward two main types of food, i.e. non-protein foods which include carrots and bananas and protein foods which include three types of cheese, fish and meat. Different techniques were necessary to manipulate each product to puff. Carrot slices may be puffed raw but the product characteristics may differ widely from those of blanched and leached slices. Some
foods such as bananas with high sugar content and cheese with high fat content may not without the addition of sufficient amount of a puffing agent. Fish and meat as fibrous protein foods need similar physical and chemical modifications, before their products can puff, such as the destruction of their fibrous structure and the
adjustment of the pH to alter their water holding capacity
to a suitable level.
The food gels may be puffed by other heat-shock
techniques other than deep-fat frying. Radiant heat was applied successfully to puff food gels such as sodium caseinate gel, starch gel, and fish product. The products could be puffed to the comparable volumes achieved by
deep-fat frying techniques, yet they were superior in some respects. They were free of fat pick-up problems. They could be rehydrated very quickly and the rehydration rate of the radiant heat puffed fish product, for example, was comparable to that of the dehydrated products of the highly sophisticated processes such as freeze-drying, and vacuum contact plate drying. [FROM SUMMARY]