Industrial Applications of Selected JFS Articles

It's the cheesiest! A number of papers in this issue study the flavor, texture, and finer points of cheese. And small wonder that so many researchers chose to study the product. According to one paper, in the United States in 2005, the most popular varieties of cheese were processed American (primarily Cheddar cheese), Cheddar cheese, and Mozzarella, with total volume sales in the supermarket of 243.3, 239.0, and 119.7 million kg, respectively. It's a big market, with some major players and lots of small, specialty manufacturers as well.

Better Pizza Cheese

Mozzarella cheese is a staple ingredient in a number of dishes that were originally Italian in provenance, but are now universal. Maximizing the production models for producing tasty “mozz” that melts the way the food producer wants it to makes everybody happy. So a group of Brazilian scientists plus a scientist from Vermont studied the effect of pH on proteolysis, calcium characteristics, and function—like melting—of Mozzarella cheese. Four different production samples of commercial cheese were used, obtained the day following manufacture, and treated with ammonia vapor and either shredded and vacuum packaged, or made into 23-mm thick chunks and vacuum packaged.

The 2 groups of samples were checked at various intervals for apparent viscosity, free oil, and water-soluble calcium, as well as hardness, springiness and cohesiveness, and meltability. pH changes were induced, and were retained through testing. Cheese pH affected functional characteristics and calcium distribution but did not affect proteolysis rates. Higher cheese pH resulted in harder cheese that needed to be aged longer to develop good melting characteristics, while cheese with lower pH values developed good melting characteristics quickly, but had a shorter shelf life.

Why is mozzarella cheese stretchy? The application of shearing forces to the hot plasticized curd aligns the para–casein matrix into dense elastic fibers that become separated by channels containing free serum and fat globules. Initially, low moisture mozzarella cheese is tough and chewy, not stretchy and tender—not what you want on a pizza. But when the cheese is refrigerated, the protein—to-protein and protein-to-calcium interactions resolve themselves into a fibrous mass with little free water, which stretches when cut, forming a flowable, succulent melted cheese that we recognize as a pizza cheese. There are fine points to the procedure, and if you're a pizza maker, buyer, or eater, you'll want to know!S443-448

Safer Juices

Fruit juice is mighty big business in the U.S., where the average consumer guzzles about 31 liters a year. The biggest component is orange juice, followed by apple juice. Keeping it salable requires inactivating microorganisms and stopping the action of enzymes and viruses. A group of scientists from the Dept. of Food Science and Human Nutrition, Univ. of Florida; the Dept. of Chemical and Food Engineering, Univ. of Salerno, Italy; and Fishery Industrial Technology Center, Univ. of Alaska Fairbanks looked for methods of inactivating microorganisms that preserved the fresh character of juices. A promising method may be dense phase carbon dioxide (DPCD), a nonthermal technology for liquid foods to inactivate microorganisms, and inactivate certain enzymes and viruses under pressures below 50 MPa without the use of high temperature treatments. High-pressure carbon dioxide (CO2) dissolves into water to form carbonic acid (H2CO3), which dissociates into bicarbonate (HCO−3), carbonate (CO−3) and hydrogen ion (H+). Pressure has a direct effect on the solubility of CO2 (pressure increases the solubility of CO2). With increasing temperature, solubility of CO2 decreases. The apparatus that was designed and tested allows accurate and precise measurements of the solubility of CO2 in liquid foods. The CO2 solubility in juices was significantly less than in pure water; so to reach saturation, smaller amounts of CO2 should be used during DPCD processing to reduce production costs. With the data generated using this equipment, it should be possible to develop better predictive relationships between CO2 solubility, pressure, temperature, °Brix, pH, and titratable acidity. Therefore, in industrial DPCD operations, the amount of CO2 used would be predicted, and the process would be more economical since the use of excess CO2 would be eliminated. E439-445

What Is That Flavor?

Farmstead Cheddar cheeses with natural bandage wrappings have a distinctive flavor profile that reminds some consumers of bell peppers. The flavor designated as earthy/bell pepper (EBP) flavor has been previously recognized and is characterized as alkylmethoxypyrazine compounds. This study is reported in “Characterization of Alkylmethoxypyrazines Contributing to Earthy/Bell Pepper Flavor in Farmstead Cheddar Cheese.” A Farmstead cheese is defined as any type of cheese that is manufactured where the cows are milked. They are typically manufactured from unpasteurized milk and aged for more than 1 y prior to marketing. Eight cheeses were divided into inner, outer, rind, and wrapper sections, and tested for descriptive sensory and instrumental analyses. They were either not detected in inner and outer sections of the cheeses or were present at low concentrations. Sensory analysis of mild Cheddar cheese model systems confirmed that direct addition of those individual alkylmethoxypyrazines (0.4 to20 ppb) resulted in EBP flavor. C632-638

The Flavor of Rice

In “Relating Sensory Descriptors to Volatile Components in Flavor of Specialty Rice Types,” researchers from the Univ. of Georgia determined a set of descriptive sensory tools that could be linked with chemical analysis to predict rice varieties with favorable flavor traits. Noting the need for a systemic method for rice breeders to select rice with flavor pluses, the researchers based the selection of rice flavors on volatile compounds found using gas chromatography olfactometry in 13 samples of specialty rice from Korea. Nineteen aroma attributes in cooked specialty rice samples were evaluated by 8 trained panelists and statistically correlated to the concentration of aroma-active compounds derived from GC–O analysis. Aroma descriptors included popcorn, cooked grain, starchy, woody, smoky, grain, corn, hay-like, barny, rancid, waxy, earthy, and sweet aroma using Stepwise multiple linear regression. The corresponding chemical aroma compounds were matched to the sensory attributes. These models help provide a quantitative link between sensory characteristics of commercial rice samples and aroma volatile components desirable in developing a rapid analytical method for use by rice breeders to screen the grain for superior flavor quality. The key compound responsible for the aroma of rice was reported as 2-acetyl-1-pyrroline, which possesses a popcorn-like aroma. Nonscented rice varieties have a higher amount of n-hexanal, other alkanals, and 2-pentylfuran than scented rice. The information is intended to help rice breeders develop varieties with good flavor characteristics in addition to the agronomic traits such as yield, standability, and weather resistance. S456-461

Cranberry Juice for Those Who Can't Stand the Added Sugar

Researchers from the Dept. of Biology, Winona State Univ., Winona, Minn.; the Philip E. Marucci Center for Blueberry and Cranberry Research and Extension, and Dept. of Plant Biology and Pathology, Rutgers-The State Univ. of New Jersey, New Brunswick, N.J.; and the Dept. of Internal Medicine, Mayo Clinic College of Medicine, Rochester, Minn. reported their findings about the effect of certain fruit juices in their paper titled “Favorable Glycemic Response of Type 2 Diabetics to Low-Calorie Cranberry Juice”, noting that fruit and vegetable intake is often low in Type 2 diabetics who have problems with glycemic control. They opined that cranberry juice may provide a means for increasing fruit intake and simultaneously producing health benefits. This single crossover design compared metabolic responses of type 2 diabetics to unsweetened low-calorie cranberry juice, carbohydrate-sweetened normal calorie cranberry juice, isocaloric low-calorie sugar water control, and isocaloric normal calorie sugar water control (NCC) interventions. Flavonols, anthocyanins, and proanthocyanidins were quantified with HPLC, LC-MS, and MALDI-TOF, including an original characterization of several large oligomeric proanthocyanidins. Metabolic responses within the 2 high- and 2 low-calorie beverages were virtually identical; however, exposure to potentially beneficial nutrients was greater with cranberry juice. Relative to conventionally sweetened preparation, low-calorie cranberry juice provides a favorable metabolic response and should be useful for promoting increased fruit consumption among type 2 diabetics or others wishing to limit carbohydrate intake.

Say the researchers, “Cranberry fruit contains a rich polyphenolic content, including A type proanthocyanidins, which have antiadhesion activity against P-fimbriated uropathogenic E. coli. Cranberry polyphenolics are also associated with improved protection of LDL from oxidative injury lipoprotein profiles, and endothelium dependent vasodilation. Cranberry products may be protective against CVD and UTIs, and people with diabetes should benefit from CBJ consumption. However, one caveat is that most commercially available cranberry juice products contain an artificially-added carbohydrate load and may be unsuitable.” Low calorie sweeteners can make cranberry juice palatable, and therefore usable for diabetics who must control glycemic impact but would benefit from the effect of cranberry on CVD and UTIs. H241-245

The Flavor of Mild Cheese

Despite the lack of a legal (or even customary) definition of how much aging changes mild Cheddar to another type, consumers like cheddar cheese that falls within a particular category. In “Consumer Preferences for Mild Cheddar Cheese Flavors”, scientists from the North Carolina State Univ. and Clemson Univ. documented the flavor profiles among commercially-labeled mild Cheddar cheeses and characterized whether consumer preferences existed for specific mild Cheddar cheese flavors or flavor profiles.

Flavor descriptive sensory profiles of 22 commercial Cheddar cheeses labeled as mild were determined using a trained sensory panel and an established cheese flavor sensory language. Nine of the Cheddar cheeses were selected for consumer testing. Consumers tasted the cheese and discriminated between the 9 cheese samples, identifying 4 distinct flavor clusters. The key drivers of liking for mild Cheddar cheese were: color, cooked/milky, whey and brothy flavors, and sour taste. Consumers have distinct flavor and color preferences for mild Cheddar cheese. These results can help manufacturers understand consumer preferences for mild Cheddar cheese, and formulate cheese that consumers can depend on. S449-455