Textured and shaped oilseed protein food products

The major emphasis in developing textured and shaped protein foods has been with the use of soy proteins. The availability at a low stable price, the high protein content and quality, and the inherent chemical properties of the protein allowing for unique structure development are major reasons for its strong world-wide use. The changing economic trends of many basic protein foods are creating a need for the use of unique textured proteins either as ingredients in existing foods or allowing improved functionality in new products. The two main procedures for texturing and shaping oilseed protein are spinning of protein isolates, and direct extrusion of flour. The spinning technique is more expensive and has greater product functionality in contrast to the direct extrusion method. Consumer acceptance is in large part correlated with the technological success of imparting desirable colors, flavors and textural properties in the finished food product. Examples of these variations are given. The use level of these textured proteins, particularly in meat products, are restricted by labeling standards. The present regulations are not clearly defined. Current proposals for labeling textured vegetable proteins when used with meat products involve standards on a ratio to meat basis. One of 21 papers presented at the Symposium, “Oilseed Processors Challenged by World Protein Need,” ISF-AOCS World Congress, Chicago, September 1970.     

Quantitation of cholesterol oxidation products in unirradiated and irradiated meats

A method to detect 7-ketocholesterol, cholesterol-5β,6β-epoxide, cholesterol-5α,6α-epoxide, 4-cholesten-3-one, 4,6-cholestadien-3-one and 4-cholestene-3,6-dione in unirradiated and irradiated beef, pork and veal was developed by use of chloroform-methanol-water extraction, solid-phase extraction, column separation, thin-layer chromatography and gas chromatography. This method recovered 78–88% of the cholesterol oxidation products and detected the cholesterol oxidation products at 10 ppb or higher. Irradiation of the meats to a dose of 10 kGy increased these compounds, except 4,6-cholestadien-3-one for all three types of meat, over unirradiated, and except cholesterol-5α,6α-epoxide and 4-cholesten-3-one for the pork. All the cholesterol oxidation products in the unirradiated meats increased during storage at 0–4°C for 2 wk with some exceptions for the pork. The increases of cholesterol oxidation products in stored irradiated meats were greater than those in the unirradiated.     

Utilization of vegetable proteins in meats of large cross sectional area

Comminuted meat products such as luncheon meats, sausages, paté, etc, and whole meat cuts such as ham, corned beef, steaks, and roast are two principal forms in which meat is consumed. Soy protein products have been used in comminuted meat products for several years. New developments have made it possible to incorporate isolated soy protein into large pieces of muscle tissue. A brine containing isolated soy protein is injected or massaged into the muscle using cured meat technology. Alternately, the intact muscle pieces can be injected first with brine and then the protein incorporated by massaging or tumbling. This process can be used to increase yield 20–40% over the green weight. Product quality attributes include normal appearance, improved firmness and slicing characteristics over brine-cured hams, combined with less weepage under vacuum packaging.     

A quantitative comparison of the yields of radiolysis products in various meats and their relationship to precursors

A detailed analysis has been made of the composition of radiolysis products formed in beef, pork, ham, and chicken. The yields of the various compounds are related linearly to irradiation dose, and the fat, fatty acid and triglyceride composition of the meats.     

Vegetable proteins in meat products,problems and possibilities

The author considers the use of vegetable protein products in the meat industry promising. Development will probably be slower than anticipated, but the use is likely eventually to become quite substantial. One may even anticipate products which replace certain traditional meat products altogether. Nutritionally such development would be completely acceptable. It should also be acceptable from a consumer’s point of view, provided adequate information is given in each case. In this respect one may note that information given to the consumers about the composition of traditional or contemporary mixed meat products is quite inadequate in many instances. The specific restrictions often placed on the use of vegetable protein products appear as adherence to tradition more than a real concern for consumer’s protection or health.     

Aflatoxins in hull and meats of cottonseed

We have found that when aflatoxins are a contaminant of cottonseed, they may be distributed both in the hulls and in the meats. The concentrations in hulls and meats do not appear to be correlated. Aflatoxins were found in hulls and not in meats of some seed samples, and the reverse situation also was observed. The amounts of toxins were generally much greater in meats, which contained up to 10,200 ppb, than in hulls, which contained up to 390 ppb aflatoxins. Hulls as well as meats fromAspergillus flavus-damaged seed represent a potential source of aflatoxin contamination, and both should be analyzed in order to accurately assess the total aflatoxins in seeds. Crops Research Division, ARS, USDA. So. Utiliz. Res. Dev. Div., ARS, USDA.     

Indentation Fatigue in Random and Textured Alumina Composites

The effect of grain orientation on contact fatigue behavior has been investigated by using alumina with elongated grains as a model system. Two kinds of composite microstructures, textured and random, were prepared by controlling the processing conditions. The textured material has the platelets aligned parallel to the surface, and the random material has the platelets randomly oriented. The Hertzian indentation results show that, although both materials exhibit damage accumulation with increasing number of cycles due to frictional degradation at the microstructural level, the damage evolution rate is much lower for the textured material. This suppression of fatigue damage in the textured material appears to result from the lower shear stress concentration along the textured weak interfaces between elongated alumina grains. The implication of the present results for structural design in improvement of contact-fatigue resistance is also addressed.     

Technical problems and opportunities in using vegetable proteins in dairy products

The food processing industry is giving increased emphasis to the production and utilization of alternate protein isolate products as functional and nutritional ingredients in an expanding number of formulated food products. Alternate protein sources such as soy and other vegetable proteins offer additional flexibility in formulating foods due to their economics, availability, functionality and nutritional properties. This paper discusses needs for developing soy and vegetable protein isolates with improved flavor, color and functionality for producing simulated dairy foods. It also considers alternative technologies for incorporating soy and vegetable proteins into the formulation so that they may function properly for forming stable solutions, emulsions, foams and gels that resemble those in their natural dairy food counterparts.     

Catalysts of lipid peroxidation in meats

Hemoprotein and non-heme iron components are active catalysts of lipid peroxidation. The behavior of these two catalysts under a number of conditions was compared as a basis for a study of their activities in meats. In model systems, MetMb accelerated linoleic acid peroxidation in a pH range from 5.6 to 7.8; it catalyzed especially rapidly at higher pH. A complex of ferrous ion [Fe(II)] and EDTA, a non-heme iron model, in a 1:1 ratio accelerated peroxidation at lower pH; no catalysis took place above pH 6.4. Most chelating agents eliminated Fe(II)-EDTA catalysis, but had no effect on MetMb catalysis. Reducing agents, on the other hand, accelerated Fe(II)-EDTA catalysis but inhibited MetMb catalysis. In model systems in which fresh dilute (1.2%, w/v) meat homogenate was the catalyst, the effect of the heme predominated. An exception was ascorbic acid; it accelerated oxidation at pH 5.6. The pattern of linoleate peroxidation catalyzed by heme-free (H₂O₂-treated) beef homogenate and shrimp homogenate was similar to that in the Fe(II)-EDTA model system. Again, ascorbic acid accelerated the catalysis and the acceleration could be eliminated by adding chelating agents. The presence of a non-heme iron catalyst in meat is thus indicated. Evidence is presented for both types of catalytic activity in meats. In cooked meats, heme was the dominant catalyst, but significant lipid oxidation, apparently catalyzed by a non-heme iron-type catalyst, occurred in cooked meats in which the heme had been destroyed by H₂O₂. In raw meats, lipid oxidation was inhibited at high pH because of removal of oxygen by enzymatic reducing systems. Both heme and non-heme iron were active at lower pH values. EDTA inhibited lipid oxidation during storage, presumably by its demonstrated effect on non-heme iron catalysis. Ascorbic acid also inhibited lipid oxidation, probably indirectly by keeping the heme pigment in the catalytic inactive ferrous state. One of 28 papers presented at the Symposium, “Metal-Catalyzed Lipid Oxidation,” ISF-AOCS World Congress, Chicago, September 1970.     

Toughness Anisotropy in Textured Ceramic Composites

In this investigation, a model predicting toughness anisotropy in textured ceramics containing elongated grains and in composites reinforced with rod-shaped particles is presented. The model predictions are based on the assumption that crack deflection is the only toughening mechanism. In the model, toughness anisotropy is calculated as a function of texture degree. For composite materials, the volume fraction of the reinforcement phase is also an input parameter. Correspondence between model and experiment was established by comparing measured toughness anisotropies in β-Si₃N₄ and Al₂O₃/SiC whisker composites to model predictions. In these model predictions, measured orientation distributions from hot-pressed and hot-forged specimens were employed. The potential for relating other toughening mechanisms in a similar format is also addressed, since the model and experimental measurements give different results. The crack deflection model simultaneously overpredicts the toughening enhancement and underpredicts the toughening anisotropy observed in the experiments.     

Methods for detection and determination of vegetable proteins in meat products

Soy protein is the vegetable protein that is most frequently used in meat products. Accordingly, detection and determination procedures have mainly been focused on soy proteins. Cereal proteins received far less attention analytically, let alone the less conventional vegetable proteins. Every method published has only a limited applicability, determined by both the type of soy preparation concerned and the heat processing of the sample. The methods may be divided into five categories. 1. Chemical methods are based on analysis of tracer substances accompanying the soy proteins by nature. Their specificity is rather low; other vegetable proteins may contain the same substances. Soy flour, concentrates and texturates respond quantitatively, and sometimes even qualitatively, different. The methods are almost useless for isolated soy proteins. 2. Microscopic methods may allow rapid detection of soy products except isolates. They may be used for quantitation purposes. However, representative results will only be secured at the expense of time and labor. 3. Electrophoresis methods rely on the recognizability of soy protein bands in the pherogram pattern. Field of application and specificity are satisfactory. Efficient media enable complete solubilization of soy protein from meat products, if not severely heat-processed. 4. Immunochemical methods, although very sensitive and specific, are only suitable for detection purposes, provided the sample temperature did not exceed 100 C during processing. This holds, of course, only true if the soy produced used is not excessively heated during preparation. 5. Methods based on amino acid composition or sequence are based on computer matching of the amino acid pattern of the meat product sample with those of varying mixtures of all proteins that could be contained in the sample.