Industrial Applications of Selected JFS Articles


There's more to structure function understanding than health claims! Research into the specific qualities of foods continues, and as more information surfaces that explains the effect of heat, chemicals, water, and pressure on specific structures, the closer the industry can come to providing foods with longer shelf life and greater food safety. And just in time: food safety is an issue, brought about by consumer's insistence on fresh flavor and texture. Most of this research is presented very precisely, but as the reader thinks about the specifics, some generalities may be better understood as well. When it comes time to think about broad issues and major problems that must be solved, having information that approaches the problem gives the problem-solver power. We need all of the power we can get.

Injection Method Improves Salmon Quality

Temperature, brine concentration, injection volumes, and needle densities all affected fillet weight gain and affected the final salt content, fillet concentration, and muscle gaping. The degree of affect was studied, using increased brine concentration (the usual 12 percent concentration was increased to 25 percent salt content; double injection techniques were compared with the single injection method). The researchers, from Norconserv AS, Seafood Processing Research and the Norwegian Inst. of Fisheries and Aquaculture Research, Seafood and Industrial Processing Div. reported in “Injection-Salting of Pre Rigor Fillets of Atlantic Salmon (Salmo salar)” found that increasing brine concentration(12% to 25%) significantly increased the initial and final contraction (24 h after injection) of pre-rigor fillets. Increased brine concentration significantly reduced weight gain and increased salt content but had no significant effect on muscle gaping. The temperatures tested did not significantly affect weight gain, fillet contraction, or gaping score. Double injections significantly increased weight gain and salt content compared to single injections. Injection-salting is used to provide satisfactory salt contents and homogenously distribute the salt into the muscle of pre rigor fillets of Atlantic salmon before the fish is dried or smoked. The paper deals with the differences that the rigor state of the fish makes in adding the salt that is required and its effects. The study was funded by the Norwegian Fishery and Aquaculture Industry Research Fund (FHF) and The Norwegian Seafood Association (NSL). p E29-35.

Injection With Cryoprotective Agents Produces Better Fish Texture

Cryoprotective ingredients such as sorbitol, combined with sodium tripolyphosphate, alginate, and alginate plus soy protein isolate in various amounts and combinations were added to red hake flesh to determine which agent would best protect the white fish which is considered susceptible to freezer burn and texture change. In “Evaluation of Various Infused Cryoprotective Ingredients for Their Freeze–Thaw Stabilizing and Texture Improving Properties in Frozen Red Hake Muscle” researchers from the Univ. of Rhode Island found that alginate was effective in preventing frozen fish muscle from hardening. This occurred because the alginate chelated calcium ions that triggered crosslinking via calcium ion bridge. When used in frozen red hake mince, soy protein had been found, in earlier studies, to reduce the free water available for ice crystallization, and prevented high levels of cross-linking from occurring. However, in whole fillets, injection with cryoprotectants appeared to provide better quality when the fille t was frozen over time. The research was partially supported by the National Fisheries Institute. p C56-64.

When Oil Selection Changes the Value of Stir-frying

The effect of stir-frying on broccoli and other vegetables which contain glucosinolates as well as lots of flavonoids, vitamins, and mineral nutrients was shown to be affected by the kind of edible oils used in preparing stir-fried dishes. Researchers from C.E.B.A.SC.S.I.C., Food Science andTechnology Dept., Espinardo (MURCIA), Spain. published their findings in “The Effect of Edible Oils on the Phytochemical Composition of Broccoli”. The researchers provided a baseline of the total intact glucosinolates, total phenolics, vitamin C, and minerals (potassium, sodium, calcium, magnesium, iron, manganese, zinc, and copper) in the edible portions of freshly harvested broccoli (florets) prior to stir-frying the vegetable in a range of different edible oils, including refined olive oil, extra virgin olive oil, sunflower oil, peanut oil, soyabean oil, and safflower oil, which are known and used worldwide.

Results showed that during stir-frying, phenolics and vitamin C were more affected than glucosinolates and minerals. When broccoli was stir-fried in extra virgin olive, soybean, peanut, or safflower oil, the glucosinolates content of the cooked broccoli compared well with the uncooked sample. The vitamin C content of broccoli stir-fried with extra virgin olive or sunflower oil was similar to that of the uncooked sample, but greater than those samples stir-fried with other oils. The paper includes a great deal of information about the particulars of cooking methods on various vegetables, and would be important for food processors, and for commissary operations in food service. p S64-68.

Soft Cookies!

A great deal of study into different combinations of sugars has been reported in the literature, and studies to reduce the hardening of soft cookies has resulted in a large body of research, as well as some major lawsuits in which most major cookie processors became embroiled, landing in the witness stand, explaining why their combinations didn't or did fall under current patents of the time. The protection of soft cookies from hardening has also resulted in packaging research. Researchers from the Univ. of Minnesota have now reported on more information about the activity of sugars in cookie systems in “Effect of Raffinose on Sucrose Recrystallization and Textural Changes in Soft Cookies.” These and similar studies have attracted such leading lights as Levine and Slade, and the current authors, Labuza and Belcourt, who elected to study the effects of raffinose, a small but mighty sugar that causes beet sugar processors to lose productivity as it interferes with sucrose crystallization. Suspecting that raffinose might do the same in cookie formulas, the authors studied systems that included sucrose (as normal cookies do), plus raffinose. The study showed that sucrose recrystallization and redistribution of moisture (both of which reduce plasticizer volume) are very significant factors in the firming of soft cookies. When raffinose was added, the formula showed reduced initial sucrose
crystallization and slowed the rate of crystallization during storage, providing cookies that were less firm. The researchers noted that while the addition of raffinose slowed firming, it probably would not provide a suitable solution to cookie hardening, as it causes various physiological difficulties for consumers. But the studies of sucrose crystalline structure may provide more information about other ways to keep those cookies soft longer. p C65-71.

Finding the Best Sources of Antioxidants in Corn

Researchers from Brazil studied the effects of corn varieties and processes on the content of lutein and zeaxanthin, antioxidants of particular interest to consumers concerned about cataracts and age-macular degeneration. In their paper, titled “Processed and Prepared Corn Products As Sources of Lutein and Zeaxanthin:Compositional Variation in the Food Chain”, the researchers studied the differences in the antioxidant materials in corn as consumed: in boiled corn, fried and boiled polenta, ready-to-eat cereals, canned corn, and cornmeal. They found that there were differences between processed products and between brands of the same product, with canned corn having the highest concentration of zeaxanthin, cryptoxantahin, and beta-carotene. The corn flake breakfast cereal had the second highest zeaxanthin. Corn meal, untoasted, had a high lutein content, and also a significant amount of zeaxanthin. Corn and corn products are important sources of zeaxanthin and lutein worldwide. However, there is wide variation in the levels of these two carotenoids in processed and prepared corn, which is due mainly to varietal differences in the raw material and to varied and substantial losses during processing and preparation. The researchers concluded that selective programs to provide varieties with characteristics for more of these important antioxidants and work with processors to keep the materials intact in food as eaten would be helpful. p S79-85.

Ohmic Heating May Provide New Starch Treatments

Ohmic heating, which was studied during the 1990's for a fast method of heat sterilization of particulate foods, may find new applications for processing starches into new thickeners and other products. “Thermal Characteristics of Ohmically Heated Rice Starch and Rice Flours” describes work by a group of researchers from Louisiana State Univ. providing new information about the effect of electric current on granule structure of rice. The amount of heat, which is generated inside the food, is known to be related to the current by the gradient in the field and electrical conductivity, so that higher electric field strengths and lower frequencies have a linear relationship with electrical conductivity, permitting food being treated to reach a target temperature faster. Starch gelatinization is inhibited, and ohmic heating at low voltage can produce starches that are “cooked out” at lower temperatures, and can produce different products when the heating is applied to products with different lipid and protein concentrations. By changing voltage, different characteristics can be produced. Since rice starch has a particularly small granule size, and is generally low in lipid, it would be interesting to see the results using other starch sources. p C84-88.

Making Omega-3 Fatty Acids Useful in Fortified Foods

A diet rich in omega-3 fatty acids is difficult to maintain, especially in consumers who don't eat fish. Because omega-3 fatty acids have been considered unstable in storage, researchers from Rutgers Univ. developed a cookie filling that protected the fatty acids from oxidation, using a matrix of starch and gelatin. The resulting products and their characteristics are described in “Stability and Consumer Acceptance of Long-Chain Omega-3 Fatty Acids (Eicosapentaenoic Acid, 20:5, n-3 and Docosahexaenoic Acid, 22:6, n-3) in Cream-Filled Sandwich Cookies”. The resulting cookies were stored at 18 and 35° C in atmospheric and vacuum packaging. The cookies kept most of the fatty acids intact for 28 d storage (loss was about 5%), and the cookies were well liked by test populations. While a number of products have been introduced containing a variety of deodorized fish oils, this approach, adding only the omega-3 fatty acids, may offer some particular advantages to a population that dislikes the flavor of fish, even at low concentrations. p S49-54.

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