EVALUATION OF A SLIDING PIN CONSISTOMETER FOR MEASUREMENT OF THE HARDNESS AND SPREADABILITY OF BUTTER AND MARGARINE

A sliding pin consistometer (SPC) has been shown to be particularly suitable for the assessment of hardness and spreadability of butter and margarine. It appears advantageous over other methods in that it is portable, self-compensating for wear, and is convenient and rapid to use on undamaged samples in their original packaging. Four products, hard and soft butter, and hard and soft margarine, with product temperatures in the range 0.8 to 20.0deg;C, were used. The hardness and spreadability of these products at these temperatures were also scored by a panel of 21 adults using a 9-point scoring scale. SPC measurements explained 96% of the variation in panel scores for both hardness and spreadability. The maximum panel score for spreadability was at an SPC value of 5.5 × 10⁻²N for all four products. The SPC should prove useful to manufacturers of butter and margarine in assessing consumer preference for their products.     

Shiraz berry size in relation to seed number and implications for juice and wine composition

This study was conducted over three seasons on irrigated Shiraz grapevines growing in a warm climate. We addressed the question of whether differences in berry size (within a population of berries from minimally pruned, own‐rooted or Ramsey‐grafted vines), would lead to differences in juice composition, wine composition or wine sensory score. Predictably, berry mass was found to increase with seed number, but berries in the smallest mass categories (0.3–0.7 g) still had similar juice soluble solids and pH; and similar concentrations of K+, tartaric acid and malic acid, compared with larger berries (1.4–2.0 g). Only for the very smallest mass category (0.3–0.55 g) was there any indication of better colour density (both for own‐rooted and Ramsey‐grafted vines) or higher anthocyanin concentration (for own‐rooted vines) compared with larger berries (1.4–2.0 g). Concentrations of tartaric acid and K+ in berry skins were highest in the smallest berry mass categories (0.3–0.7 g) and decreased with increasing berry mass (up to 1.4–2.0 g). A strong correlation (R²= 0.85) between skin tartaric acid and K+ concentrations was observed across that range. Small‐scale wine lots based on small berries (0.8–0.9 g) versus large berries (1.2–1.3 g) showed no differences in measures such as soluble solids, total acids or pH of juice; nor any differences in pH, total acids, K+, tartrate, malate, spectral characteristics or sensory score of corresponding wines. Moreover, small berries had a similar skin to fruit ratio, and a similar juice yield, compared to large berries. However, when measured post‐fermentation, the ratio of seed weight to skin weight was higher for small berries. The mass range of berries used here for small‐scale winemaking (i.e. from 0.8–0.9 g up to 1.2–1.3 g), covered the range of Shiraz berry mass typically found in irrigated vineyards (from 0.8 to 1.5 g), and thus confirms the relevance of present outcomes to practical winemaking. Finally, our data for variation in juice and wine composition as a function of berry size, showed consistent trends for all seasons, and thus implies that reported instances of improved wine quality from small berries (often associated with certain pruning treatments or deficit irrigation strategies), are more likely due to treatment effects that lead to small fruit, rather than to intrinsic developmental differences between large and small berries.     

ISOLATION OF BDELLOVIBRIOS THAT PREY ON ESCHERICHIA COLI O157:H7 AND SALMONELLA SPECIES AND APPLICATION FOR REMOVAL OF PREY FROM STAINLESS STEEL SURFACES1

Predatory bacteria of the genus Bdellovibrio that prey upon Escherichia coli O157:H7 and Salmonella species were isolated from soil and sewage samples. Bdellovibrio isolates 45k (from soil) and 88e (from sewage) attacked and lysed the E. coli and Salmonella strains tested, with log₁₀ reductions ranging from 2.5 to 7.9 CFU/mL after 7h incubation, using a two-membered culture system. The predators showed activity against the bacteria within the temperature range of 19 to 37C. Bdellovibrio isolate 45k reduced a population of E. coli dried on stainless steel surfaces by 3.6 log₁₀ CFU/cm² following 24 h contact time and at a 10:1 predator to prey ratio and was also effective in reducing the level of biofilm cells. Bdellovibrios can potentially be utilized for removal of bacteria from surfaces of food processing equipment and possibly for controlling the growth of pathogenic and spoilage bacteria in foods.     

Characterization of Starch and Fiber of Banana Fruit

Mature green and ripe bananas were analyzed for moisture, protein, starch, sugars, ash, and fiber. Ripe banana fruit contained 1.27% dietary fiber, as determined by the detergent method. Hemicellulose content was higher than that of most fruits and vegetables whereas cellulose and lignin contents were lower. The morphological and physicochemical properties of isolated starch were determined. Starch granules were irregularly shaped, with spheroid and elongated forms predominating. Both the Brabender amylograms and the two-stage swelling patterns of the starch were similar to those reported for mung bean starch.     

Oil-in-Water Emulsions Stabilized by Sodium Caseinate or Whey Protein Isolate as influenced by Glycerol Monostearate

Competitive adsorption between glycerol monostearate (GMS) and whey protein isolate (WPI) or sodium caseinate was studied in oil-in-water emulsions (20 wt % soya oil, deionized water, pH 7). Addition of GMS resulted in partial displacement of WPI or sodium caseinate from the emulsion interface. SDS-PAGE showed that GMS altered the adsorbed layer composition in sodium caseinate stabilized emulsions containing < 1.0 wt % protein. Predominance of β-casein at the interface in the absence of surfactant was reduced in the presence of GMS. The distribution of α-lactalbumin and β-lactoglobulin between the aqueous bulk phase and the fat surface in emulsions stabilized with WPI was independent of the concentration of added protein or surfactant.     

Effects of Sodium Tripolyphosphate on Physical and Sensory Properties of Beef and Pork Roasts

Six paired beef round and pork loin roasts were used to determine the effects of sodium tripolyphosphate (STPP) on fresh and reheated roasts. Roasts were pumped 10% of their weight with distilled water (control) or with distilled water containing 4.75% STPP. Roasts were cooked to internal temperatures of 70°C (beef) or 75°C (pork) and evaluated after 0, 1 or 3 days (roasts were reheated to cooked temperatures). This study indicates that phosphate in pork and beef roasts allowed them to be reheated after 1 and 3 days of refrigeration with minimal losses of juiciness, tenderness or flavor intensity, Phosphate injection reduced warmed-over flavor in reheated pork roasts but was not successful in decreasing the incidence of warmedover flavors in reheated beef roasts.     

Modelling the deep-fat frying of beef meatballs

Mathematical models describing heat, moisture and fat transfers during deep-fat frying of beef meatballs were developed and validated against experimental data consisting of temperatures at two locations in the product, and average moisture and fat contents. Fat diffusivity in the product was 0.287 × 10^-7m²s^-1 while fat conductivity followed Eyring's model with frequency factor of 0.137 × 10^-6m s^-1 K^-1 and activation energy of 2.70 kJ mol^-1.     

MEASUREMENT OF PEA TENDERNESS

The effect of pendulum inertia on Pea Tenderometer readings was examined by recording the pendulum angle and the torque that it applies to the peas during a test. The effect was significant at the critical point in the test cycle where the torque is at a maximum. It was concluded that this affects the standardization of the Tenderometer.     

CNC夜间加工的三种思维模式变化

对于今天的许多机器车间而言,最有希望的潜在扩张途径不是新市场或增加设备,而是那些未开发的、无人值守的夜间工作时间,这些时间可以被用于自动化的"熄灯"生产. 当前,人力问题成为车间生产主要局限.有资源进行扩张的车间经常会面临不断寻找或培养各类人才的局面,对于人力要求不高且长时间独立运行的机器成为主要需求.尽管如此,对于大...