QUALITY OF COFFEE CREAMERS AS A FUNCTION OF PROTEIN SOURCE

Many U.S. consumers add a sweetener or creaming agent to their brewed coffee. An ideal creamer, when added to coffee, should remain stable, dissolve readily, and provide whitening ability. In general, these properties are imparted by the protein component. Four different proteins – sodium caseinate, isolated wheat protein, soy protein isolate and whey protein concentrate – were used to formulate coffee creamers, individually and in combination, and the resultant creamers were evaluated for functionality. Coffee creamers containing plant proteins had significantly greater apparent viscosity but lower L* values than did creamers made with dairy proteins. Creamers made with higher concentrations of isolated wheat protein exhibited syneresis, whereas no syneresis occurred if sodium caseinate was the predominant protein. Only the creamer formulated with soy protein isolate alone exhibited feathering when added to hot, brewed coffee. These results indicate that coffee creamers can be formulated with plant proteins and sodium caseinate.     

MODIFIED WHEAT STARCHES USED AS STABILIZERS IN SET-STYLE YOGURT

Yogurt was formulated with gelatin; native wheat starch (NWS); and modified wheat starches (MWS) (acetylated cross‐linked, hydroxypropylated, or hydroxypropylated cross‐linked). Yogurt samples were evaluated for chemical (fat, total solids, pH, titratable acidity); microbiological (yeasts/molds and lactic acid bacteria); and physical (rheological, textural, color, syneresis) properties during 60 days of refrigerated storage. Yogurt formulated with NWS exhibited a significantly greater storage modulus (G′) and firmness compared with yogurts prepared with MWS. Minimal syneresis was measured in all yogurt samples. The titratable acidity of yogurt samples increased and pH decreased during storage. Yeasts/molds were not detected while lactic acid bacteria counts decreased ～ 1 log CFU/g by day 60 in all yogurt samples. This study showed that the characteristics of yogurt formulated with NWS and gelatin were similar, so NWS may be used as an alternative stabilizer. The MWS stabilized yogurts were stable but had different consistencies than gelatin‐ and NWS‐stabilized yogurts.     

Biologically Active Components Inactivation and Protein Insolubilization during Heat Processing of Soybeans

Inactivation of lipoxygenase, trypsin inhibitor, urease and retention of protein solubility during water blanching of dehulled soybeans at 90°, 95° and 100°C were investigated. Lipoxygenase was the most heat labile, followed by urease and then trypsin inhibitor. Processing time based on “acceptable inactivation time” (AI) was proposed. AI value was longest for trypsin inhibitor, followed by urease and then lipoxygenase. The combined effect of heat on protein solubility and biologically active components inactivation was expressed as “PDI at acceptable inactivation time” (PDIAI). PDIAI value for the processing “limiting factor,” trypsin inhibitor inactivation, at the three temperatures were 36.7%, 42.5%, and 34.8%, respectively.     

Solid-Phase Acid Extraction Improves Thiobarbituric Acid Method to Determine Lipid Oxidation

Samples (110g) of raw (17.2–22.6% fat) and cooked 12.6–16.4% fat) ground beef in plastic cups were stored aerobically at 4±1°C. Lipid oxidation was measured by four versions of the thiobarbituric acid (TBA) test, including aqueous acid extraction-C₁₈ (TBA-C₁₈), direct heating, distillation, and unmodified aqueous acid extraction; and by sensory evaluation of rancid odor after 0, 2, 4, 6, and 8 days storage. The TBA-C₁₈ method was more specific (P <0.05) and its limit of determination was 20 times lower than the other methods in detecting malonaldehyde. Results correlated (r = 0.856 to 0.883 in raw, and r = 0.936 to 0.981 in cooked meat) with sensory evaluation scores.     

Effect of Algin/Calcium Binder Levels on Various Characteristics of Structured Beef

Six levels of algin/calcium binder (0, 0.28, 0.57, 0.85, 1.13, 1.42%) were evaluated in raw and cooked structured beef. Binder levels of 0.57% gave higher cook yield and greater cooked product bind scores than products without binder. Sensory evaluation scores for product bind and hardness increased (P< 0.05) with higher binder level for raw samples, but hardness showed no differences for cooked samples. Force required to penetrate raw samples increased up to the 0.85% binder level, but snowed no difference (P>0.05) among cooked samples. Raw product bind scores increased with higher levels of binder, while cooked product bind scores were similar with binder levels above 0.57%.     

Modified Atmosphere Packaging Protects Market Quality in Broccoli Spears Under Ambient Temperature Storage

Broccoli spears were packaged using a semipermeable polymeric film and stored 96 hr at 20°C. CO₂ and O₂ concentrations within the packages equilibrated to about 9 and 3%, respectively. Relative to non-packaged spears, ascorbic acid, chlorophyll and moisture retention were greater; and peroxidase activity was lower in packaged broccoli. No differences were found in total aerobic microbial population growth or Instron shear values between packaged and control spears.