Effect of Feathery Mottle Virus Infection on Sweet Potato Sensory Properties

Four sets of sweet potato clones obtained by meristem tip culture were used to investigate the effect of feathery mottle virus (FMV) infection on the appearance, sensory quality and chemical composition of the storage roots. This study, encompassing four generations, indicated that FMV infection had a slight effect on carbohydrate metabolism but no effect on the polyphenoloxidase-phenol system. Flavor and texture profile analyses indicated that for one clone, FMV-infected roots were more desirable when baked than healthy roots. Considering the study as a whole, FMV infection did not appear to adversely affect sweet potato sensory properties. Clones produced from the same parent by meristem tip culture might have different compositional and sensory properties.     

Alaska Pollock (Theragra chalcogramma) Mince and Surimi as Partial Meat Substitutes in Frankfurters: N-Nitrosodimethylamine Formation

Studies were conducted to determine the feasibility of using 3 forms of Alaska pollock (AP) as a partial substitute for meat in a nitrite-cured product. The effect of several pre- and post-processing storage conditions on N-nitrosodimethylamine (NDMA) were studied in frankfurters substituted with 15 and 50% unwashed and washed mince and surimi. In franks made with unwashed mince, frozen stored prior to processing, NDMA increased during frozen storage; little change was observed in franks containing washed mince and surimi. Refrigerated storage of franks generally showed a decrease in NDMA with all 3 forms of fish. Overall, the use of washed mince and surimi at the 15% substitution level gave mean values less than 2 ppb NDMA, even after boiling. The results indicate that 50% unwashed AP mince should not be used as a partial substitute for meat in frankfurters.     

纵向旋转切削加工对环形零件畸变的影响

通过旋转试验和有限元分析介绍了工件在切削加工过程中产生的畸变情况，分析了工件的装夹方式、切削速度、切削深度和进刀量对100Cr6钢环圆度的影响。通过去应力退火释放冷加工诱发的残余应力后工件的圆度与切削参数有关。另外测试了被试验环的表面残余应力，其表面残余应力与装夹方式有关。将测量的装夹力作为计算参数输入，通过有限元分析方法测试了装夹方式对工件变形的影响。协同测量结果示出了装夹方式影响工件变形的一个主要因素，表面残余应力与工件的径向变形有关，最大的拉伸应力位于夹口位置。旋转切削试验结果表明，提高切削速度圆度会稍有增加；随着切削深度的加大，圆度呈下降趋势，尽管切削力增加了；进给量的增加会导致更高的切削力，因此圆度值也增加；常规的去应力退火可使被加工环的圆度值增加。     

A Comparison of Methods for Polyuronide Methoxyl Determination

A comparison was made between three basic methods for determining methoxyl (OMe) groups in a polyuronide, viz., step-wise oxidation-reduction initiated by hydriodic acid, neutralization of de-esterified carboxyl groups with potassium hydroxide, and direct combustion of methanol by gas chromatography. Accuracy and precision of the methods were ascertained by analyzing methyl fuorate. All the methods were accurate. The neutralization and gas chromatographic methods had major advantages of simplicity and shortness of time of completion over the hydriodic acid/bromine method. Dimethylsulfoxide in the the saponification medium had no special effect.     

HIGHER AVERAGE MERCURY CONCENTRATION IN FISH FILLETS AFTER SKINNING AND FAT REMOVAL

Ten male and ten female brown trout (Salmo trutta L.) ranging in weight from about 500 to 3500 grams were caught in Lake Ontario. Opposite sides of each individual fish were randomly processed and trimmed to yield skinned or unskinned fillets. Skinning resulted in an increase in the average concentration of total mercury in the fillets of fish of either sex but the increases were not significant .
With the exception of the unskinned fillets of the male fish, the concentration of mercury in the fillets increased significantly as the weight of the fish of either sex increased. The fillets of the male fish appeared to be higher in mercury than that in the corresponding fillets of female fish of comparable weight. In all instances, the concentrations of mercury in skinned and unskinned fillets were well below the 1 ppm fresh weight action level of the U.S. Environmental Protection Agency.     

RESIDUES OF p, p'-DDE AND DICOFOL IN MILK OF DAIRY COWS FED COMMERCIALLY PRODUCED APPLE POMACE

Residues of the miticide, dicofol, used in orchards, as well as p,p'-DDE a metabolite of p,p'-DDT present as an impurity in dicofol, were found in each commercial apple pomace sampled at several locations in Central New York. Traces of dicofol and p,p'-DDE were found in milk when cows were experimentally fed one of the pomaces for 9 days. These compounds were also detected in the milk of cows which had been fed by a dairy farmer on a practical basis for several months. It was judged that the milk residues were too low to be of health significance to consumers.     

Chemical, Physical, and Sensory Properties of a Sweet Potato French-Fry Type Product During Frozen Storage

Chemical, physical, and sensory properties of a sweet potato Frenchfry type product were determined after 0, 3, 6, 9, and 12 months frozen storage. Analyses included measurements of dry matter, sugars, alcohol insoluble solids, carotene, vitamin C, color, texture and sensory panel scores for color, flavor and texture. Few changes were observed except for an appreciable loss (58%) in vitamin C and an apparent increase in carotene (27%). A partial drying treatment before freezing increased the rate of ascorbic acid loss. For the fried product, no appreciable storage-induced changes were noted in the sensory scores for color, flavor and texture thus indicating that the product had good stability in frozen storage.     

RELATIONSHIP BETWEEN INSTRUMENTAL AND SENSORY PARAMETERS OF COOKED SWEETPOTATO TEXTURE1

This study compared two instrumental methods, namely uniaxial compression and texture profile analysis (TPA), with sensory evaluation in describing the textural properties of cooked sweetpotatoes. The steamed cooked samples (1.35 × 2.2 cm cylinder) of four cultivars and six selections were subjected to a trained texture profile panel for sensory ratings and the two instrumental methods for determination of the mechanical properties. Factor analysis indicated that the 15 sensory variables were grouped into 3 main factors, namely moistness-firmness (factor 1), particles (factor 2), and fiber (factor 3). Among the instrumental parameters, shear stress of compression and fracturability, hardness, and gumminess of TPA correlated highly (R = 0.73–0.95) with both the mouthfeel and mechanical-type sensory notes. These parameters of the two instrumental methods were linearly related (R²≥ 0.95) and could be converted from one to another with a high degree of reliability. Regression equations based on shear stress significantly explained (R²= 0.71–0.91) eight of the sensory notes. These instrumental parameters can be good predictors of cooked sweetpotato texture.