Virginia Polytechnic Institute and State University

Susan Duncan, Dairy and Sensory Evaluation

Bill Eigel,                Food Biochemistry

Joe Marcy:               Food Processing

Merle Pierson: Food Microbiology

 Sean O’Keefe: Food Chemistry

Susan Sumner:   Food Safety

Walter Hartman:    Dairy Plant Manager whartman@vt.edu

Kim Waterman:  Dairy Chemistry    Kwater@vt.edu

Brian Yaun: Microbiology byaun@vt.edu           Phone: (540) 231-8697

Current research at virginia tech    

Have a wonderful Christmas Season and a Happy New Year!!

Current research at virginia tech

 Effect of Antioxidants on the Oxidative Stability of Edible Fats and Oils:  Thermogravimetric Analysis

   Thermogravimetric analysis (TGA) was used to determine the oxidative stability of various edible oils (olive oil, milkfat) and triacylglycerides (triolein, trilinolein, and tristearin). The effect of natural (a-tocopherol, ascorbic acid) and synthetic antioxidants (butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and tertiary butyl hydroquinone (TBHQ) on the oxidative stability of trilinolein was also evaluated.  Oil resistance to oxidation was obtained by measuring the increase in sample weight due to the uptake of molecular oxygen, the temperature at maximum sample weight, and the temperature at the onset of oxidation.  When comparing sample weight increase, trilinolein proved to be oxidatively less stable than triolein, olive oil, and milkfat, while triolein was less stable than olive oil and milkfat.  Tristearin, a saturated triglyceride, showed no increase in sample weight.  Olive oil showed significantly higher stability than milkfat when comparing the temperature at the onset of oxidation.  When comparing effectiveness of antioxidants, a combination of 0.01% BHA and 0.01% BHT most improved oxidative stability of trilinolein.

 HOT TOPICS AND DAIRY ISSUES

 Milk Drink that Lowers Blood Pressure

   Mjolkursamsalan, Iceland’s largest dairy company, is manufacturing a blood pressure lowering milk drink using the patented Evolus technology developed by Finland’s Valio.  The Finnish company launched its Evolus fermented milk on the home market in 2000, and it is the first product using Valio’s technology to be launched outside Finland.  It also is the first product to be sold in Europe with a scientifically established claim to control blood pressure.  The new drink, introduced under Mjolkursamasalan’s LH brand, contains milk-derived, natural tripeptides that have clinically been shown to control blood pressure.  The bioactive peptides result from fermenting milk casein with certain lactic acid bacteria. The L. helveticus bacterium, widely used in cheesemaking, splits casein to the ile-pro-pro and val-pro-pro tripeptides that reduce blood pressure.  The effect of Evolus in lowering blood pressure has been documented in several clinical trials, including a recent study published in the American Journal of Clinical Nutrition.    

   Evolus has found a successful market in Finland, where consumption of fermented milk products is part of the traditional diet.  Because it is a fresh product, its distribution is limited, and Valio has been looking for licensing partners outside the domestic market.  Mjolkursamsalan already holds the rights to Valio’s technology for the probiotic bacteria lactobacillus GG (LGG), a patented L. rhamnosus strain, so the Evolus licensing, signed this year, is a logical extension of co-operation between the two companies.  The new LH fermented milk is available in 100 ml plastic bottles and comes in 3 flavors – apple-pear, cherry and strawberry.  Finland’s largest dairy company also offers its technology for lactose-free milk to dairy food makers.

Membrane Filtration and Coagulation Technology for Mozzarella Cheese Manufacture

   Researcher Syed Rizvi of Cornell University has been developing a novel process for the production of Mozzarella-style cheese without the cheese vat.  The cheese can be made on a continuous basis by using a combination of microfiltration systems and coagulators.  The procedure has the added benefit of being able to capture virgin milk proteins, which are becoming increasingly valuable in health, wellness and nutraceutical applications. 

   Starting with a smaller quantity of microfiltered and concentrated skim milk, Rizvi is able to efficiently produce a “zero” whey Mozzarella cheese and pure milk proteins.  “With the microfiltration process, dairy processors can filter liquid milk to remove serum proteins before using the milk in cheesemaking”, said Rizvi.  “Depending on whether the goal of the process is to make a concentrated milk-derived food ingredient rich in protein, or to separate individual components from milk, the filters can be adjusted accordingly, yielding a customized fluid permeate and a customized retentate.”

    Rennet and starter culture is added to the high-concentrate casein retentate to yield cheesemilk that is pumped into a coagulator.  The curd is then cooked, salted and stretched.  “This process lends itself to the continuous production of Mozzarella-style cheese, allowing manufacturers to meet a spike in consumer demand for their product,” said Rizvi.

   New research has shown that milk-derived proteins may prove beneficial for weight management, muscle metabolism and hypertension.  The microfiltration process, in addition to other new and improved milk fractionation methods, provides a means to isolate milk proteins and incorporate them into high-protein and other products that consumers are requesting. 

Pizza Hut Launches “Healthier Pizza”

   Following other fast food chains in developing healthier fare, Pizza Hut is introducing a lower-calorie pizza with half the cheese of the Dallas-based chain’s Thin ‘N Crispy pizza.  The new Fit ‘N Delicious pizza also has 25% less fat and 30 fewer calories per slice than a comparable Thin ‘N Crispy.  A slice from a large Fit ‘N Delicious pizza has 150 calories vs. up to 450 calories per slice from Pizza Hut’s Stuffed Crust Pizza.

   The target market for the leaner Fit ‘N Delicious pizza is women ages 29-54.  More tomato sauce as well as leaner meats also contribute to the calorie reduction in the new pizza.  Company spokesperson Julie Hildebrand said, “Our focus groups tell us that people who thought pizza couldn’t fit into their lifestyle are now reconsidering it because they have this lower fat option.  So we think this will bring in new traffic to Pizza Hut, and could actually result in us using more cheese.”

   It took six months for the nation’s top pizza chain to develop the leaner pizza, which rolled out nationwide at the end of October.

 Product Recall - Deli Chef Sour Cream and Cheese Macaroni Salad

    November 23, 2003 – The recall was initiated when a sample taken from a Kroger deli service counter by the State of Georgia tested positive for Listeria moncytogenes.  Consumers should not consume the recalled products, manufactured by KB Specialty Foods in Cincinnati, OH. 

   The product is distributed through deli service counters in Kroger stores in AL, GA, SC, TN, IL, IN, MI, MO, OH, KY, AK, MS, NC, VA, WV, LA and TX.  Distribution of this product also takes place through Food 4 Less stores in MI, through Dillan Stores in AK, KS, MO and OK; and through Owen’s and Pay Less stores in IN.  No illnesses have been reported to date.