JFDS v77n10 Industrial Application Briefs-October 2012

Food mixtures gain increased importance as testing increases for labeling purposes, and as regulators and legislators move closer to a “good food”/“bad food” mode of thought. Just about all foods are mixtures at one level or another. While it may appear on a label as, for example, “tomato”, the components are complex, and issues of bioavailability cause rethinking about process parameters. The more we know, the more we need to know. Complex instrumentation makes it possible to better understand the contents and interactions, while simplification of methods based on this knowledge allows testing to be current, appropriate, and inexpensive enough to use as needed.

Cholesterol Quantification Method Uses Fewer Steps, Time

Simpler methods for analysis of complex materials are generally a plus for the food industry and for regulatory groups as well. In “A Novel Sample Preparation Method Using Rapid Nonheated Saponification Method for the Determination of Cholesterol in Emulsified Foods”, a method for quantifying cholesterol in foods such as infant food and formula reduces the steps for sample preparation from 14 individual steps to only 6. Time would vary depending on how the equipment was set up, and the efficiency of individual technicians, but the possibility of a rapid test prep would be very welcome, especially as the accuracy is within range, and less heating is required. This would be especially important in certain foods, where cholesterol could be altered by the heating steps. Given the increased frequency of testing that appears popular with regulatory agencies, rapid testing helps to hold the cost of testing down, which helps keep the cost of food down as well. C1042–C1046

Farm-Raised Catfish Offers Incentives for Improved Processes

Farm-raised catfish has gotten to be a big deal in the U.S. and other fish farming areas. U.S. farmers produced, and processors sold, some $423 million worth of catfish nuggets, strips, and similar products. Normally, to keep enough oxygen in the water, algae is cultivated in the ponds. The problem with this culturing step is the absorption of geosmin and 2-methylisoborneol compounds produced by the algae. In “Evaluation of a Modified pH-Shift Process to Reduce 2-Methylisoborneol and Geosmin in Spiked Catfish and Produce a Consumer Acceptable Fried Catfish Nugget-Like Product”, researchers described how the acid-shift process (finely-divided portions of catfish are mixed with water and acids are added to bring the pH to about 3, at which point fish proteins can be separated from the fat and the earthy-smelling compounds from the algae) can be enhanced through the use of shaker-sieves instead of centrifugation to capture the water-soluble protein. The method of depuration—leaving the fish in pure water for a period of time to remove the algae by-products—was used as a control. This method, used by many fish farmers, is expensive and delays harvest. The results were that consumer panels preferred the texture of the nuggets produced by the acid-shift method but liked the flavor of the depurated catfish. The researchers concluded, “Application of the pH-shift process on catfish fillet tissue effectively reduced amounts of GEO, MIB, moisture, ash, and collagen. Although concentrations of GEO and MIB in fillet tissue were reduced by almost 50%, the reductions observed in this study were not enough to obtain a consumer acceptable catfish product. However, sensory attributes such as texture and overall acceptability were observed to be improved by the pH-shift process. The texture issue is a point to remember, as better methods of handling the flavor emerge. S377–S383

Better Understanding of the Antioxidants in Tomato

Possibly because of the flurry of excitement over lycopene a number of years ago, the antioxidant quality of tomatoes remains of interest. Over the last decade, a number of isomers of lycopene have been identified, and the changes that occur because of heating are a little better understood. Because tomatoes are widely consumed both cooked and raw, the characteristics of this important antioxidant are intriguing. In “Effects of Heat Treatment on the Carotenoid and Tocopherol Composition of Tomato”, researchers found that heating directly affected the isomerizarion of E lycopenes to Z isomers while changes in β-carotene, α-tocopherol, and γ -tocopherol were less influenced by the various heat treatments. The researchers believe that “thermal processes might break down cell walls and enhance the release of carotenoids and tocopherols from the matrix, as well as increase isomerization of lycopene and β-carotene.” It is suggested that the easier release of these compounds with heat may translate to higher bioavailability of antioxidants from heated or heat processed tomato products. C1109–C1114

Understanding the Onset of Ripening May Help Manipulate Fruit Harvest

In the paper “Decrease in Fruit Moisture Content Heralds and Might Launch the Onset of Ripening Processes”, researchers studied the concomitant events of water reduction, ethylene action, and ripening. Say the researchers, “We found decline in water content occurring at the onset of ripening in climacteric and nonclimacteric fruit, suggesting that this phenomenon might be universal. This decline in water content persisted throughout the ripening process in some fruit, whereas in others it reversed during the progression of the ripening process.” Further, “we propose that a metabolic shift to an oxidative state in ripening fruit is manifested by oxidative cross-linking of fruit cell wall. Oxidant-driven cell wall tightening might, in turn, lead to reduction in the wall and fruit tissue moisture content and, apparently, a state of water stress that might stimulate the onset of ripening processes.” A better understanding of what initiates ripening will be essential to adapting plants to climate change, and to accommodating the length of time for shipping fruits ever-increasing distances. S365–S376

A Reason for Meat & Potatoes?

In “Effects of Potato Fiber and Potato-Resistant Starch on Biomarkers of Colonic Health in Rats Fed Diets Containing Red Meat”, researchers studied the effects of red meat plus potato fiber and potato starch on the microbiota of the rat's large bowel colonies. The rats, when fed red meat, fared differently depending on what source of carbs was included as part of the diet. But generally, the potato ingredients improved the environment for production of healthy bacteria and the short-chain fatty acids. The researchers suggest that formulating red meat products with suitable carbs might improve the products for red meat eaters. Or maybe Dad was right—who needs more than steak and potatoes. H216–H223


Placing potato sticks (French Fries, if you will) in an upright position in the fryer produces a less fatty, crisper and better tasting goody. In “Effect of Potato Orientation on Evaporation Front Propagation and Crust Thickness Evolution during Deep-Fat Frying”, researchers tell us why, and how they found out. When measured by a complex system using tiny thermocouples and calipers, it is found that the crust at the vertical side surface is the thickest, whereas the crust at the horizontal bottom surface is the thinnest. In addition, the former crust is crispy, compact, and very dry, while the latter is soft, pliable, and not so dry. So stand those Fries up like little soldiers, and produce a healthier, tastier product. E297–E305

Understanding the Red Dragon

The Red Dragon fruit, or red pitaya as it is popularly known, features a bright red color, plus lots of potassium, fiber, and antioxidants. In “Isolation and Identification of Lactic Acid Bacteria from Fermented Red Dragon Fruit Juices” researchers adapted biochemical methods to the identification of about 21 different isolates of lactic acid bacteria found in fermented red dragon juice. The authors found that 2 different species of LAB, E. faecalis and E. durans, were identified by using RFLP and nucleotide sequencing of the 16S rRNA gene. They noted; “Although E. faecalis is used in food production, its risk to human health cannot be neglected. Further investigation of E. faecalis at the strain level is important to justify its suitability to be incorporated into food and beverages or the elimination of the microbial population in fermented red dragon fruit juices has to be done before it can be consumed.”M560–M564