Objective measurement of texture variables in raw and processed French fried potatoes

The five most important variables encountered in french fry production and texture measurement are: specific gravity, raw potato storage, raw potato firmness, freezing of fried product, and cooling of hot french fry slices. Shear force curves are presented to illustrate the effects of these variables. A double maximum cruts shear peak is exhibited by properly processed french fried potatoes when they are hot. Bursting of the crust is less evident with less desirable fries and with frozen and reheated samples. Shear press punch tests proved to be best for analyzing raw potato firmness. In order to determine and study the texture variations within a potato, Durometer³ tests were conducted on concentric zones and sections from bud to stem end of most firm and least firm raw tubers. Higher resistance to penetration was encountered in the most firm potatoes. Durometer values vary directly with solids within a tuber which can be explained by certain morphological conditions. Because of turgidity, however, solids and Durometer values vary inversely between firm and non-firm tubers. A table is presented which lists the texture inferences derivable from changes which occur in the french fried potato shear force curves.     

Potato tuber stem-end fry color determination

Precise measurement of tuber stem-end fry color is necessary to determine the fry quality of potatoes (Solanum tuberosum L.). Changes in fry color as influenced by small variations in measurement location, delays between slicing and frying, and delays between frying and measuring were examined. Variations in time between frying and measurement, and variations in the location of measurement contributed more to changes in observed color than delays between slicing and frying. The standard visual method for determining stem-end fry color was compared to objective methods using a Photovolt reflectance meter. Photovolt reflectance readings of two types of transverse stem-end tuber slices were compared with those from longitudinal strips. All methods produced closely related re-sults. Optimum sample size and applications for each method are discussed.     

Evaluation of Different Cooking Conditions on Broccoli (Brassica oleracea var. italica) to Improve the Nutritional Value and Consumer Acceptance

The objective of this study was to gain insights into the effect of the cooking method on the liking as well as the retention of glucosinolates in broccoli. With this knowledge it can be concluded whether the health aspects of broccoli be improved by the cooking method without deteriorating sensory perception. For this, broccoli was cooked by methods commonly applied by consumers: boiling with a cold (water) start; boiling with a hot (water) start; and steaming. Firmness, greenness and amount of total glucosinolates in cooked broccoli were instrumentally determined. Sensory evaluation by untrained consumers (n?=?99) for liking and sensory attributes intensity rating were performed on broccoli cooked by steaming and boiling-cold start at three time points, which resulted in ‘high’, ‘medium’, ‘low’ firm broccoli samples. At the end of cooking, steaming showed an increase in the amount of total glucosinolates (+17 %). Boiling-hot start (?41 %) and boiling-cold start (?50 %) showed a decrease in amount of total glucosinolates. Sensory evaluation did not show statistically significant differences between steaming and boiling-cold start in liking at ‘high’ and ‘medium’ firmness; and in the attribute intensity ratings (except for juiciness at ‘medium’ firmness, and flavour at ‘medium’ and ‘low’ firmness). This study demonstrates that medium firm broccoli showed optimum liking and that steaming compared to boiled-cold start showed higher amount of glucosinolates. It is concluded that the health aspects of broccoli can be improved without reducing the sensory aspects by optimising the cooking method.     

Bison,a new red-skinned potato variety

Bison, a new red potato, was introduced by North Dakota State University. This new red variety has smooth tuber type and bright red skin color. Bison yields somewhat less than Norland and Red Pontiac but the advantage of Bison over these two varieties is its uniformity and bright red color. Bison is about medium in total solids and makes chips comparable in color to Norchip but lighter in color than Kennebec. Bison is resistant to race 0 of the late blight organismPhytophthora infestans, but susceptible to race 1–4.     

Use of tetrahymena pyriformis to evaluate the relative nutritive value (RNV) of some crop cultivars and processed cereals

Tetrahymena pyriformis was used to compare the relative nutritive value (RNV) of various components of wheat and rye bread. Rye bread crumbs were superior to those of wheat crumbs. The crust of both breads had considerably reduced RNV. When applied as an intervarietal screening tool in barley, this organism failed to detect small differences in the lysine content. Gross differences among various cereals and legumes could be detected. A colorimetric method for biomass measurement was compared with the direct microscope counting and found to be superior. The merits and limitations ofT. pyriformis as a test organism in the RNV determination are discussed.     

A rapid method for determining blackspot susceptibility of potato clones

Two methods of determining susceptibility of potato clones to blackspot were compared: (1) bruising by weight dropping and (2) bruising by abrasive peeling. A highly significant positive correlation was obtained between the intensity of enzymatic discoloration following abrasive peeling and the amount of blackspot that developed by weight dropping (r=0.93). Abrasive peeling was more rapid than the weight-dropping method. Tuber samples were abraded 30 sec and the amount of enzymatic discoloration evaluated after 24 hr. The need for individually bruising and hand peeling of tubers was eliminated with this method. Because of the rapidity of the abrasive peeling method, it can be used effectively in potato breeding programs to screen large numbers of clones for blackspot susceptibility. Results indicate that tuber maturity affects enzymatic discoloration and blackspot susceptibility. Immature tubers, dug while the vines are still green, are more resistant to blackspot than mature tubers. Tuber maturity therefore must be considered when screening clones for susceptibility to blackspot.     

Environmentally benign scouring of wool fibers using mesophile acidic lipase

Surfaces of raw wool fibers possess high amounts of greasy substances that need to be removed prior to further processing. Acidic lipases using Bacillus licheniformis (MTCC 2618) were produced with the optimum activity levels closer to the room temperature. Scouring of wool fibers using mesophile acidic lipase has been attempted, in the present work, as an alternative to the existing alkaline treatment and the samples were assessed in terms of weight loss, moisture regain, tenacity, elongation, surface appearance, and friction of the fibers. The lipase scoured wool fibers showed moisture regain and weight loss values comparable to that of alkaline treatment, with lower static and dynamic frictional coefficients. Higher tenacity and elongation values were observed in the lipase scoured fibers compared to the alkaline scoured samples and clear appearance of the surface, compared to the raw wool fibers, was also observed in the lipase scoured samples.     

Internal quality of Russet Burbank potatoes following chilling

Russet Burbank potatoes were chilled at 25 F (?3.8 C), 27.5 F (?2.5 C), or 30 F (?1.1 C) for various periods of time and were then held at 45 F (7.2 C) for one or four weeks before testing. Susceptibility to injury was quite variable between the two crops and among tubers of the same lot exposed to the same treatment. The greatest amount of low temperature breakdown occurred in tubers chilled at 27.5 F (?2.5 C) for 10 hours. Flesh color, reducing sugar content, mealiness, and amount of sloughing in tubers that survived chilling were not markedly different from those in control samples although certain trends were observed indicating that the quality of chilled tubers was beginning to deteriorate. Chilling increased yellowness of flesh color in most treatments and darkness in several. Chilled tubers had a reducing sugar content slightly to moderately higher than the controls. They sloughed less than the controls and tended to be less mealy     

Properties of starch and dietary fibre in raw and processed quinoa (Chenopodium quinoa,Willd) seeds

We investigated certain properties of starch in raw and in heat-treated samples of quinoa, properties that are of importance to the nutritional quality of an infant food currently being developed. Scanning electron microscopy of the starch in raw seeds showed polygonal granules (0.6 to 2.0 µm diameter) to be present both singly and as spherical aggregates. Thermograms (DSC) of the flours showed one transition phase for gelatinisation of the starch and another for the amylose-lipid complex. The gelatinisation temperature of the starch was 67°C. Cooked samples manifested the highest degree of gelatinisation (97%), followed by the drum-dried (96%) and autoclaved (27%) samples. Separation of the starch on a SEPHAROSE CL-2B column showed the quinoa starch to be affected by the heat treatment, manifesting changes in the degree and extent of degradation. The amylograph viscosity of the quinoa flour showed no distinct peak for pasting, but the viscosity remained constant after gelatinisation. Cooking and autoclaving modified the viscosity of the paste. The drum-dried sample manifested a higher initial viscosity at 25°C. Thein vitro digestibility of raw quinoa starch determined by incubation for 60 min with -amylase was 22%, while that of autoclaved, cooked and drum-dried samples was 32%, 45% and 73%, respectively. Saponins did not affect the digestibility of the starch, though they tended to increase the amylograph viscosity. The total dietary fibre content in the cooked sample (11.0%) was significantly lower than that in the autoclaved (13.2%), drum-dried (13.3%) or raw samples (13.3%), while the insoluble dietary fibre fraction in the samples did not change with heat treatment. However, as compared with that of raw quinoa, the soluble dietary fibre fraction was reduced significantly both by cooking (0.9%) and by autoclaving (1.0%).     

Detection of potato viruses X and S in tissue culture plantlets

The latex agglutination test (LAT) and enzyme-linked immunosorbent assay (ELISA) were evaluated in separate studies for their ability to detect potato virus X (PVX) and potato virus S (PVS) in tissue culture plantlets. Healthy and infected clonal lines of several potato cultivars were used. LAT was unsatisfactory because only low levels of agglutination were obtained with infected samples, and because variable and inconsistent results were obtained with both healthy and infected clones. ELISA, however, consistently gave high spectrophotometric readings and intense visual reactions for infected but not for healthy clones. The results indicate that ELISA can be used to detect PVX and PVS in tissue culture plantlets, and in programs where tissue culture is employed, early detection and elimination of infected plantlets is possible.     

Modeling the functional compression properties of hand-knotted carpets using factorial design and response surface methodology

The most performance quality of cut-pile carpets is related to mechanical behavior of surface piles under compression loading in use. In this study, main purpose was to achieve the predictive models of the functional compression properties of carpet including work of compression (WC), compressional resilience (RC), linearity of compression-thickness curve (LC), and thickness loss (TL) after recovery on hand-knotted carpets with symmetric (Turkish) knot. Eighteen hand-knotted carpet samples with different structural specifications were produced. Meanwhile, compression properties were investigated in new and worn out carpet samples by a Hexapod tumbler tester in 4000 and 12000 revolutions. Factorial experimental design and response surface method were applied for modeling of each compression properties. To optimize the initial models the Box-Cox transformation was used. In the final models, contribution of different variables was also determined. The models showed a desirable fit and high adjusted R² values were observed. The ANOVA test showed that the obtained models are valid at 5 % level significant.     

Rapid extraction and solubilization of potato starch with Dimethylsulfoxide

Dimethyl sulfoxide (DMSO) solubilization of starch from lyophilized potato tissue is equally quantitative and more convenient than solubilization in dilute alkali, especially when analysis of a large number of samples is necessary. Starch extraction with DMSO decreases the handling time of each sample by eliminating sonication, filtration, and centrifugation steps required by the NaOH solubilization technique.     

Preparation and thermal properties of polyphenylene sulfide/organic montmorillonite composites

Cetyl trimethyl ammonium bromide (CTAB) was used for the intercalation modification of nano-montmorillonite (MMT). The spectra of Fourier transform infrared spectrometer (FTIR) and X-ray diffraction (XRD) suggested that CTAB had intercalated into the layers of MMT. And the interlayer spacing of MMT increased from 1.198 to 3.616 nm. The thermogravimetric analysis (TGA) curves of organic montmorillonite (OMMT) showed three-step degradation. The scanning electron microscope (SEM) photographs showed that surface morphology of MMT remained unchanged. Then polyphenylene sulfide (PPS)/organic montmorillonite (OMMT) composites were prepared by melt blending. And composites were treated at 180 °C for 24 h. The results of SEM showed that OMMT had good dispersion behavior and adhesion with PPS. The results of differential scanning calorimetry (DSC) showed the addition of OMMT resulted in heterogeneous nucleation crystallization of PPS. The results of TGA showed there was a good improvement of the thermal stability of PPS. The FTIR and color measurement analysis showed the addition of OMMT could improve the thermal oxidation stability.     

Effect of domestic processing on zinc bioavailability from ricebean (Vigna umbellata) diets

The effects of various processing methods viz. pressure cooking with soaking, sprouting (48 h), sprouting and pressure cooking, dehulling, and pressure cooking of the dehulled legume on the bioavailability of zinc were studied. The total zinc content varied from 3.28 to 3.37%; the highestbeing in raw ricebeans and the lowest being in dehulled, soaked and pressure cooked, and sprouted and pressure cooked ricebeans, respectively. The soluble zinc content was highest for dehulled soaked and pressure cooked ricebeans (28.2%) and lowest for raw ricebeans (16.0%). The absorption, retention, and balance of zinc were estimated in rats fed experimental and standard ZnSO₄ diets using a balance study. The maximum retention of zinc wasobserved in dehulled soaked, and pressure cooked diets (63.37%) followed by sprouted (48 h) and pressure cooked (61.38%) diets. The gain in body weight, total femur zinc and retention of zinc in liver, kidneys and spleen were found to be highest for rats eating the sprouted pressure cooked diet followed by the dehulled, soaked and pressure cooked diet. Plasma zinc levels were found to range from 3.81 to 6.34 mol/dl; they were maximum for rats fed the dehulled, soaked and pressure cooked diet. It can be concluded that dehulling significantly improves the availability of zinc and germination of ricebeans is the best method to enhance the zinc availability.     

Influence of Colorado potato beetle sample counts and plant defoliation on potato tuber production

Field experiments were designed to subject Superior potato plants to various levels of defoliation by the Colorado potato beetle (CPB)Leptinotarsa decemlineata (Say), Coleoptera: Chrysomelidae. Defoliation occurred during each of five consecutive plant growth periods and CPB population, plant leaf area, and tuber weight data were recorded for each period. A visual defoliation rating scheme provided an accurate estimate of actual potato plant leaf area of defoliated plants. Data generated from regression analysis demonstrated a significant dependence of leaf area on CPB numbers per plant during some plant growth periods, but numbers of CPB accounted for very little of the total variation in tuber weight. Plant leaf area was the most important independent variable in the tuber weight regression model.     

Effect of Cooking Procedures and Storage on Starch Bioavailability in Common Beans (<Emphasis Type="Italic">Phaseolus vulgaris</Emphasis> L.)

Common commercial beans were cooked using two procedures: under pressure (autoclaving) and traditional cooking. Total starch extraction was higher in beans cooked with the traditional procedure (41.69–42.81%) than in the autoclaved samples (37.04–38.16%) and did not change during storage at 4 °C. However, available and total resistant starch levels in vitro were not influenced by the cooking procedure or storage. Retrograded resistant starch content was higher in beans cooked with the traditional process (2.65–2.79%) than in autoclaved beans (1.62–1.94%). The initial in vitro -amylolysis rate in freshly cooked beans was higher in the autoclaved preparation than in the beans cooked by the traditional process, but final hydrolysis indices (90 min) were similar for both samples. None of the bean samples showed statistical differences in -amylolysis behavior (=0.05) after storage at 4 °C for 96 hour.     

Some aspects of potato appearance and texture. III. Sampling tubers for cation analysis

Individual unpeeled Kennebec tubers were analyzed after being subdiviled in various ways for sampling. The individual portions were wetashed whith a nitric-perchloric mixture and three cations were determined by Atomic Absorption Spectrophotometry. Representative samples of the tubers could be obtained by using subsamples of a blend or by using two opposite sectors cut longitudinally where each sector comprised 1/16th of the tuber. The latter method gave the greatest uniformity among the subsamples. Magnesium was uniformly distributed in the tubers studied, while calcium and potassium were more concentrated in the area external to the vascular tissue and in the stem and the bud ends of the tubers. The inequality of calcium distribution was extremely great.     

Seminole: A new variety of potato combining good chipping characteristics with good field performance in Alabama,Florida, and North Carolina

Seminole (FL282 or B4469-7) is a new potato variety, named and released by the Research and Farm Departments of Frito-Lay, Inc. Its medium-early tubers are round to oblong with smooth, light cream-buff skin color. The eyes are shallow and pink. It was selected on the Research Farm, Rhinelander, Wisconsin from family line B4469, one of 399 family lines received from the National Potato Breeding Program, Beltsville, Maryland. Tested for its reaction to Verticillium wilt, it was one of the most resistant among 1,190 seedlings. It proved superior to many named and numbered varieties in specific gravity and chip color. In Alabama, Seminole produced relatively high yields of tubers with unusually high specific gravity. Tests in Florida and North Carolina gave similar results. In the South, Seminole is usually 7–10 days earlier than Sebago, and produces higher yields of tubers with higher specific gravity. Unlike Sebago, its tubers separate readily from the vines preventing losses in mechanical harvesting.     

Studying irradiation homogeneity in light aging for historical textile conservation

Instrumental light aging is one of the most important tools for restoration and conservation of historical textiles. It used in testing stability of conservation materials, in addition to its lightening effect during the presentation in the museums. Light fading is an important tool for preparing the aged textile and other polymeric samples especially for archaeological conservation applications. Many fadometers do not give homogeneous exposure for all sample’s areas. This work studies the color changes of silk fabric dyed with turmeric (Curcuma longa L.) mordanted with alum or ferric sulfate. Color change was studied for the exposure periods ranged from five to hundred hours. Three positions of different irradiance levels were measured on the same sample namely (bottom, middle and upper). Individual color change for each position was recorded and studied. The results showed that there is non-homogeneous irradiance distribution due to different positions in fadometer or mordant used.