Industrial Applications of Selected JFS Articles

We all say we are what we eat: diabetic, food poisoned, chubby, or healthy. Keeping food safe is a complicated mix of proper (you define it) diet, proper food hygiene, and education to new theories. The layman has trouble keeping up with research, as, indeed, does the food professional who struggles to keep abreast of a chosen specialty.

Organic, Conventional Tomatoes Show Lots
of Variability

A paper titled “Qualitative and Nutritional Differences in Processing Tomatoes Grown Under Commercial Organic and Conventional Production Systems”, reporting the research by a team from the Dept. of Food Science & Technology, Univ. of California, Davis, Small Planet Foods, Inc., and the Dept. of Statistics, California State Univ., employed high level statistics to try to find whether organic culture produced product that was tastier, more nutritious, or healthier than tomatoes grown conventionally. They looked at tomatoes grown on various farms, and found that there were big differences between the farms. Tomatoes grown at the Rominger farm consistently exhibited no difference in lycopene, ascorbic acid, or total phenolics in the microwaved juice as an effect of production system. On the other hand, these 3 nutrients were always higher in conventional tomatoes grown at Terranova and Harris, and conversely higher (or the same) in organic tomatoes grown at O'Neill farm. If one examines the soil evaluations, the Terranova and Harris Farms both had sandy loam soil, while the O'Neill tomatoes were grown on clay. The Rominger tomatoes (which showed no difference in nutrients) had a combination of silty clay and loam. There were also some differences in tomato cultivar and plant type, and in fertilizers and pesticides used (Table 3) at these farms. The effect of organic and conventional production systems on nutrient levels requires additional investigation because the results appear to have an interaction with the specific farm studied. Looking at the data, it appears that, just as “we are what we eat,” so are vegetables in this study what they consumed, as soil components. The researchers wanted to compare the quality and nutritional value of processing tomatoes grown on matched organic and conventional farms at 4 commercial grower locations. They were able to compare tomatoes grown under these “real life” conditions, but could study only 4 growers in the study, which restricted their conclusions to this specific group of growers. They reported “It was not possible to make statements concerning the differences between quality of organic and conventionally grown tomatoes.” They noted that, in the grower group that they worked with, there were differences even within production system (for example, organic or conventional) in fertilizer and irrigation systems, methods of pest control, and tomato cultivar planted. However, these preliminary results on a limited number of commercial growers indicated that there may be potential advantages to the use of organically grown tomatoes because of higher levels of soluble solids, titratable acidity, and consistency. This study of 4 growers indicated that both higher flavor impact and reduced energy requirement for concentration of juice may result from use of organically grown tomatoes. Their work showed that “A potential exists to affect both positive and negative attributes of fruit quality through a better understanding of the production system, whether it be conventional, organic, or something else.”p C441-451.

Useful Antiyeast Activity Identified in Garlic

The paper “Synergistic Antiyeast Activity of Garlic Oil and Allyl Alcohol Derived from Alliin in Garlic” reports the mechanisms by which this compound operates. The researchers are from Sejong Univ., Kwangjinku, Seoul and the R&D Center, Nong Shim Food Co. LTD., Korea. Garlic, Allium sativum, has been used as a spice and folk medicine since ancient times and is known to possess potent antimicrobial activity. This antimicrobial activity is due to volatile sulfur compounds derived from alliin (S-allyl-L-cysteine sulfoxide), a nonprotein amino acid formed in garlic by the action of cysteine sulfoxide lyase. It has been known that heating to high temperatures causes loss of the antimicrobial activity because the enzyme alliinase is inactivated by heating. Allicin is rapidly decomposed to diallyl sulfides the major constituents of garlic oil (GO), but GO, diallyl sulfides, and aqueous garlic extracts lacking allicin were reported not to possess antimicrobial effects. These findings were made several decades ago and, being negative, effectively turned off subsequent studies. These researchers looked at processes and combinations and found that it was possible to significantly increase the antimicrobial efficacy of plant extracts through synergistic effects using appropriate combinations. The combined use of the materials was much more effective than when used alone. p M437-440.

Better Cheddar provides Better Processed
Cheese, Too

Processed cheese (PC) is often considered a byproduct, made from leftovers. Production of PC has been increasing steadily with production being estimated at approximately 1.5 to 1.8 million tons per year, equal to approximately 10% to 12% of natural cheese production. The growing popularity of processed cheese suggests that consumers are buying it for reasons besides low price. Processed cheese has many advantages over natural cheese, and it is suggested that its better keeping qualities and diversity of products with specific flavor intensity has made it popular in its own right. Researchers at the Univ. of Cork, Ireland and the Univ. of Bascilicata, Italy studied the characteristics of cheddar, finding that a key quality factor, such as the levels of intact casein in the cheese system, will also influence the degree of emulsification, the degree of casein aggregation, and the elasticity of the final PC. Excessive proteolysis in natural cheese has been associated with textural defects in PC manufactured from the original cheese, including overshortness, faulty body, and graininess. It has been reported that PC made from mature natural cheese was softer compared to PC made from unripened cheese. It has been reported that the extent of proteolysis in the natural cheese ingredient may influence the body of PC spreads. However, these authors recognized that a clear explanation could not be offered about the differences in the body characteristics of PC spreads, due to lack of research. The study investigated the relationship between Cheddar cheese ripening, emphasizing proteolytic breakdown, and textural changes in PC that was manufactured by differently-ripened
Cheddar. This analysis clearly showed that the concentration of intact αs 1-CN in the Cheddar cheese was strongly correlated with the decrease in hardness, fracturability, springiness, adhesiveness, and G' in the corresponding PC samples. Flowability increased in the PC samples and was correlated with the production of free amino acids in the Cheddar cheese as well as development of pH 4.6 SN/TN. It was concluded from the multivariate data analysis that the degradation of αs 1-CN was the proteolytic event most strongly correlated with the softening seen in the PC samples during the first 28 d of ripening in the Cheddar cheese base. p C483-490.

Electrical Conductivity of Food Mixtures Affects Ohmic Heat Transfer

The complexity of starch gelation, especially in protein-containing mixed food systems is particularly important in products like surimi. Ohmic heating, a relatively new rapid heating method, uses electric current to heat food mixture. The resistance of the current as it passes through the food generates energy internally to increase the temperature. Ohmic heating can work with most foods, including surimi paste, because there are ionic species such as salts and acids, so an electric current can be made to pass through the food. In a conventional heating system, the lowest thermal conductivity of a particular ingredient controls its heating rate, but when using ohmic energy, the electrical conductivity is the controlling factor. Ohmic heating has been studied since the early 1990s, and many reports are in the literature, yet the complexity of the system fascinates food scientists. The paper “Electrical Conductivity and Physical Properties of Surimi-Potato Starch Under Ohmic Heating” reports the work of a team at the Seafood Research and Education Center & Dept. of Food Science, Oregon State Univ. The team studied the effects of potato starch and Pollock surimi, finding that electrical conductivity was affected by moisture content, starch gelatinization, applied frequency, and voltage. Electrical conductivity was highly dependent on temperature and resulted in a linear relationship in a surimi-starch system. However, a magnitude of electrical conductivity in surimi-starch system changed as temperature increased, more clearly after 55 °C, especially when native starch was used and/or when starch concentration increased. This indicated that starch granules in surimi-based products swelled during heating and this altered the electrical conductivity of the surimi starch system. When moisture content, applied frequency and voltage increased, electrical conductivity also increased. Whiteness and texture properties of gels decreased when the amount of pregelled starch increased and moisture content decreased. The choice of starch may be important-don't assume that a pretzel will act just like a native starch; a processed granular starch may introduce differences, too. p E503-507.

Milk and Fruit Beverages are Complex Mixtures

The color of a fruit mixture may change when added to milk, and not always in a totally predictable manner. In this instance, the fruit contains varying amounts of carotenoids and other color-providing phytochemicals, and these compounds need to be considered as active ingredients, if a processor wants to produce a constituent product. The paper titled “Carotenoids and Color of Fruit Juice And Milk Beverage Mixtures” comes from researchers at the Univ. of Valencia, Spain, where these beverages are gaining in popularity. They measured 17 commercially available “ready to drink” fortified beverages consisting of mixtures of fruit juices and milk to evaluate their carotenoid profile (including their Z/E stereoisomers) and color during their commercial shelf life. Common fruits such as apple, lemon, pear, strawberry, kiwifruit, pineapple, and banana were low in carotenoids. However, orange, apricot, mango, and peach contributed significantly to increasing cryptoxanthin and carotene concentrations. Conversion of all-E carotene and cryptoxanthin to their Z  iso-mers took place in 8 of the 17 samples containing carotene and in 9 of the 13 samples containing cryptoxanthin, respectively, which resulted in some loss of provitamin A activity and nutritional value. It seems that the popularity of these products is fairly recent, and the market may be searching for the most preferable and nutritious blends of product to insure sales. p C457-463.

Mung Bean Starches Characterized

Research teams from Dept. of Food Science and Technology,
Sejong Univ., and the Dept. of Food Science and Biotechnology, Kyung Hee Univ., Korea have characterized the starch from the mung bean, a seed that is rapidly growing in importance. Their characterization provides information that may lead to additional uses for the bean, which is now grown in Africa, as well as its traditional home in Asia, and increasingly in the U.S. “Chemical Structure and Physical Properties of Mung Bean Starches Isolated from 5 Domestic Cultivars” describes a mixed starch containing about a third linear amylase and the remainder of a unique branched amylopectin that produces a specific kind of retrograded starch, held together by zones of retrograded amylase. The bean is often used in mung bean noodles, a clear, tough noodle that is cohesive and clear. Mung bean noodles are usually made fresh, which is fortunate, as the high level of amylase mitigates against maintaining a stable structure. Even though excellent gel matrix can be made of mung bean starch, severe syneresis of the gel matrix prevents stability. The characteristics of the starch extracted from 5 domestic varieties of Mung bean were not significantly different, but the starch exhibited 2 different levels of amylopectin branching, which was not reflected in the molecular weights. The jellybean shape and the unique HPAEC profile of APs' branch-chain length distribution provide a method of identifying the starch, and the purity of it. p C471-477.