SIMULATION of CANOLA and BARLEY DRYING IN A DEEP BED

A mathematical model for a radial, continuous-crossflow dryer was modified and used to simulate the drying process in a fixed bed dryer. the predictions of the adapted model were compared with experimental test results for canola drying at the following drying conditions: airflow rates of 0.4 and 0.6 kg/(m²s), inlet air humidity 0.098 and 0.0114 kg/kg of dry air, initial grain moisture content 0.221 and 0.251 kg/kg dry basis. In both tests the inlet drying air temperature was kept at an average of 67.5°C. At the end of canola drying, the mean drying air temperature predicted by our model was within 1°C of the measured temperature and the mean predicted moisture content was within 0.5% of the measured moisture content, dry basis. Also, our model was verified against experimental results for barley published by other authors and against predictions from a published model for barley. the predictions from our model were in good agreement with the published experimental and predicted data. Simulations results for canola and barley drying in the same thickness of a deep bed were compared. Simulations were conducted to investigate the effects of canola properties such as bulk density and dryinig conditions of air such as airflow rate and air humidity on drying in deep beds of canola.     

Microstructure of Peanut (Arachis hypogaea L. cv. Florigiant) Cotyledons after Oil Cooking

The microstructure of peanut (Arachis hypogaea L. cv. Florigiant) cotyledon before and after oil cooking at 160°C (10 min) was investigated with light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Principal observations included thermal modification of the cytoplasmic network, lipid bodies, protein bodies, starch, and cell-to-cell junctions during oil cooking.     

COATING CHARACTERISTICS OF FRIED CHICKEN BREASTS PREPARED WITH DIFFERENT PARTICLE SIZE BREADING

Characteristics of coatings formed from breading of different particle sizes were investigated in breaded, fried chicken breasts. Breading was divided into three categories namely, small (particle size ≤ U.S. No. 60 mesh), medium (particle size between U.S. No. 20 and U.S. No. 60 mesh) and large (particle size > U.S. No. 20 mesh). Chicken breasts were battered, breaded and deep-fat fried for 240 s at 160C. Smaller breading particle size produced smoother and more uniform coatings. Compressive force at 80% strain was 14.3, 85.6 and 130.5 N for small medium and large particle size breading, respectively. With larger breading particle size, L* and a* color values increased, while b* values showed no significant change. Acoustical data taken during compression of coatings did not show any significant differences due to different breading particle sizes.     

LIPIDS OF CURED CENTENNIAL SWEET POTATOES

SUMMARY –Lipids isolated from cured Centennial sweet potatoes were identified and quantitated by a combination of column and thin layer chromatography. These lipids were shown to consist of 42.1% neutral lipids, 30.8% glycolipids and 27.1% phospholipids. Triglycerides and steryl esters were the major lipids of the neutral fraction. Among the phospholipids, phosphatidyl ethanolamine, phosphatidyl choline and phosphatidyl inositol were the most abundant. Galactolipids and the steryl glucosides were also present. The predominant fatty acids were stearic, palmitic, oleic, linoleic and linolenic.     

PHOTO SENSITIVITY OF FRESH MEAT COLOR IN THE VISIBLE SPECTRUM

SUMMARY –The effect of specific wavelengths of visible light on fresh meat color was investigated. 2-in. diam cores of meat were aseptically prepared from top rounds (adductor muscle and semimembranosus muscle). Freshly oxygenated face-to-face cuts were used as the sample and control. The sample and control were packaged in mylar polyethylene pouches and cooled moist filtered air was circulated through the pouch for the duration of the experiment. Samples were exposed to the following wavelengths at an energy level of 0.5 mw/cm²: 420.0, 510.0, 550.0, 570.0, 590.0 and 632.8 nm. Experiments were conducted at 34°± 1°F and 41°± 1°F for 2 and 5 days of exposure. The controls were next to the sample but kept in darkness during the exposure period. There was no temperature differential between the sample and control. Oxidized heme pigment content was determined by reflectance spectrophotometry. No wavelength enhanced the formation of oxidized heme pigment more than any other, however illuminated samples contained an average of 5.5% more oxidized heme pigment than did the controls. Oxidized heme pigment content increased with lengthened storage time and increased temperature. The increase in oxidized heme pigment content as a result of illumination may be due to a photochemical activation of a compound such as riboflavin which then may react with oxygenated heme pigments to form oxidized heme pigments.     

APPLICATION OF A NEW CONTINUOUS FLOW SPECTROPHOTOMETRIC METHOD FOR THE CHARACTERIZATION OF POLYPHENOL OXIDASE NATURALLY IMMOBILIZED ON COCONUT FIBER

The association of continuous flow injection and spectrophotometry affords a simple, novel and rapid way of monitoring continuously the activity of naturally immobilized enzymes in their natural environment, thus eliminating cumbersome purification. The method was applied to determine the activity of polyphenol oxidase (PPO) enzymes naturally immobilized on coconut (Cocus nucifera, L.) fiber tissues. Maximum enzyme activity occurred at a temperature of 25C and at pH 6.0 using catechol as substrate. Thermal stability was assayed in a temperature range of 20 to 75C. The PPO exhibited excellent thermal stability, with only 50% loss in its activity at 75C after 4.3 min exposure. For catechol apparent Michaelis‐Menten constant (apparent Km), apparent Vmax and the apparent activation energy were 9.1 × 10^?3 mol L^?1, 0.20 abs min^?1 and 10.5 kcal mol^?1, respectively. The immobilized PPO showed high activity for o‐diphenols. The reactivity order was caffeic acid > pyrogallol > catechol. Complete inhibition of the enzyme was observed with 1 × 10^?3 mol L^?1 concentration of cyanide, thiourea, L‐cysteine, ascorbic acid, sodium sulfite, nitrates of cadmium, zinc and mercury, individually. Benzoic acid, 3‐hydroxy‐benzoic acid, 4‐acetamidephenol, sodium azide, resorcinol, L‐cystine and EDTA at equal concentrations inhibited PPO partially.     

OBSERVATIONS ON TEXTURE MEASUREMENT OF RAW CUCUMBERS WITH THE FRUIT PRESSURE TESTER*

Raw fruit of a ‘firm’ (Explorer) and a ‘soft’ (Green F) cucumber cultivar were puncture tested with the Magness-Taylor fruit pressure tester (FPT) manually, and also with the FPT or only FPT tip mounted in the Instron. Puncture-values for flesh only were 70–75 % of those for intact fruit. Neither the cucumber size (1–2.5 in. diam) nor the test speed (5–50 cm min^-1) appreciably affected the puncture test values.