Recipient Organization
UNIV OF MASSACHUSETTS
(N/A)
AMHERST,MA 01003
Performing Department
FOOD SCIENCE
Non Technical Summary
Improvising the value of muscle foods can be achieved by maximizing water-holding during processing, storage, and cooking while controlling texture and minimizing lipid oxidation. This research project will address these problems by inactivating oxidation substrates and oxidants and modifying the subcellular structures of the muscle.
Animal Health Component
25%
Research Effort Categories
Basic
75%
Applied
25%
Developmental
(N/A)
Goals / Objectives
The overall objective of this work will be to enhance the value of muscle foods, especially sea foods, by improving water-holding capacity, optimizing texture and controlling lipid oxidation. To do this a deep understanding of the major components of the muscle tissue, water, proteins, and lipids is required. Out laboratory has made major inroads in these areas, some of which are now being put into commercial practice. This project will continue this work. Evaluation will be made of the components that are the primary contributors to lipid oxidation in muscle foods. In particular we shall compare heme proteins, other iron proteins and low molecular weight complexed iron. The identified pro-oxidants will be evaluated in isolated membrane systems and in washed and unwashed muscle tissue. Muscles with both high and low content of mitochondria will be examined. To date our membrane work has involved primarily the sarcoplasma particulum, but there is evidence mitochondria
also contribute to the oxidation. Control of moisture content of muscle foods is a primary factor in economic yield and quality attributes; a high-water holding capacity (WHC) is desirable. Water-holding capacity is controlled by the structural arrangement of the myofibrillar/cytoskeletal proteins. Injection technology can be used to modify the subcellular muscle structures to allow significant improvements in water-holding capacity of fresh, frozen and/cooked muscle tissue. Improvements in the water holding capacity will be achieved by learning more about the structural rearrangements of the myofibrillar/cytoskeletal proteins as affected by environmental conditions. Important commercial fish are subject to a unique stress, the breakdown of trimethylamine oxide (TMAO) to formaldehyde. When formaldehyde is produced in too high a concentration, the tissue becomes tough and holds water poorly. Our objective is to understand the causes of this effect of formaldehyde and to develop ways of
preventing it.
Project Methods
Experiments to inhibit lipid oxidation have involved trying different antioxidants. Our approach is unique in that we determine the fraction of the muscle tissue with which the antioxidant is associated, such as the oil fraction, the lipids of the cellular membranes, the proteins or the aqueous phase. In addition, we shall try to identify the primary pro-oxidants and determine the conditions that are useful in inhibiting their activity. We shall also modify the susceptibility of the most sensitive lipids, those of the membranes, by changing the structure of the membranes. Experimental work justifying all these approaches has been obtained. Our goal with proteins is to evaluate the structural constraints of the myofibrillar and cytoskeletal proteins on water holding-capacity and texture in muscle foods. This will be done by selective solubilization in homogenized, minced and intact muscle tissue. Adjustments to intact muscle tissue will be made by injection techniques.
The injection techniques use procedures that do not require phosphates but use protein isolates prepared from low value raw materials from the same species. These concepts are based on work we have done in developing what we have termed the possible solubility inhibiting polypeptides by examining the physical and functional properties of muscle tissue as these protein are selectively solubilized and in some cases removed from the tissue. The selective solubilization is done by modifying the pH and the ionic strength of the aqueous phase of the muscle tissue. A special case involves the role of the formaldehyde produced enzymically from TMAO. This compound reacts with muscle protein to make them highly insoluble and leads to poor-water holding capacity and texture. Although often considered to be caused by cross-linking of the proteins, most experimental evidence including ours shows that this is not the case. We shall take a new approach in the evaluation of the role of formaldehyde
by determining whether it functions to modify the possible solubility inhibiting polypeptides of the muscle tissue.