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Thesis (Ph. D.)--University of Wisconsin--Madison, 1962. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Studies generally agree on the critical influence of physico-chemical characteristics of raw potatoes on the physico-chemical and sensory characteristics of potato chips. However, the actual magnitude of differences in sensory quality and consumer acceptance of potato chips as a result of differences in the physico-chemical characteristics of raw potatoes are scarcely reported in most studies. This research was conducted to determine the effect of different physico-chemical characteristics of potato samples on the sensory quality and acceptance of potato chips. The potato samples which represented typical variations in physico-chemical characteristics that a potato chip manufacturer experiences were sourced over a six month period. The samples comprised of four potato varieties (A, B, C, D) sourced from five regions (V, W, X, Y, Z). The samples were coded AV, BW1, BW2, CW, CX, DY, DW and DZ. BW1 and BW2 were of the same variety and grown in the same region but harvested at different time periods. The sourcing of potatoes and potato chips were done at the manufacturer’s processing line during regular production. The potatoes were analyzed for physico-chemical characteristics generally reported to influence potato chip sensory quality, i.e. specific gravity (solids contents), starch content and reducing sugars content. After processing, the physico-chemical characteristics i.e. moisture content, colour and oil content of the respective unflavoured potato chip samples were analysed. The sensory qualities of both unflavoured and flavoured (sour cream and onion) potato chips of the respective potato samples were also determined. There were significant differences (p<0.05) in the specific gravity/solids content of the potato samples. The specific gravity and solids content ranged from 1.073 to 1.098g/cm3 and 19.2 to 24.9% respectively. Reducing sugars were not detected in any of the potato samples at a minimum detection level of 0.05 %. The potato chip samples differed significantly (p<0.05) in moisture content, oil content and colour (a * and b* values, chroma, hue angle) with ranges of 1.2 to 1.9 % (moisture), 33.1 to 40.8 % d.b (oil content), 0.39 to 3.69 (a *), 15.88 to 21.26 (b*), 15.93 to 21.37 (chroma) and 79.92 to 88.96 o (hue angle). Descriptive sensory evaluation showed that 6 and 8 of the attributes identified in the unflavoured and flavoured potato chip samples, respectively, differed significantly (p<0.05). Consumer sensory evaluation indicated that there was no clear preference of one chip sample over the others despite of differences observed through descriptive sensory analysis and physico-chemical characteristics. All the chip samples were generally liked. To the manufacturer this research could be regarded as of a quality control nature since the potato chip samples used in this study were of chipping varieties actually used by the manufacturer. The value of this research to the chip manufacturer was the fact that despite of slight differences in the physico-chemical characteristics (specific gravity/solids content and starch content) of potato samples, potato chips of acceptable sensory quality to the consumers were produced. / Dissertation (MSc)--University of Pretoria, 2011. / Food Science / unrestricted

Chipping varieties and model systems were used to determine the role of potato constituents on chip color. Composition was evaluated by HPLC and chip color measured using a ColorQuest colorimeter. Reducing sugar (RS) content did not completely explain color quality when present in low concentrations (<60 mg/lOOg). Levels of ascorbic acid, glutamine and a chlorogenic acid isomer, along with RS, showed high correlation with color. Sucrose was a poor estimator of chip color. Model systems used leached potato slices infiltrated with solutions containing sucrose, RS, ascorbic, chlorogenic and amino acids. Linear association of RS with L* and hue angle and quadratic relationship with chroma of chips were found. Ascorbic acid affected chroma and hue at low RS levels while chlorogenic acid was not involved in color development. Red potatoes {Solarium tuberosum and Solarium stenotomum) were evaluated as potential source of natural red colorant. Cultivars (33) were screened for anthocyanin content and qualitative composition. Monomeric anthocyanin content, determined by pH differential, ranged between 4 and 40 mg/lOOg fresh weight (fw) tuber. Varieties 5847-1 and ND04069-4 showed high anthocyanin content (>35 mg/lOOg). Anthocyanin composition was characterized by HPLC, spectral analysis and Mass Spectroscopy (MS). The major anthocyanin was pelargonidin-3-rutinoside-5-glucoside acylated with p-coumaric acid. The presence of glycoalkaloids (α-solanine and α-chaconine) was detected by MS and quantified by HPLC. Varieties NDO4069-4 and 5847-1 showed glycoalkaloid levels of 13 and 7 mg/lOOg fw, respectively. Glycoalkaloids were precipitated from pigment concentrates by alkaline treatment. The best results were obtained at pH 8.0 with 30% monomeric anthocyanin degradation and 90% glycoalkaloid precipitation. The color and pigment stability of chemically related anthocyanin extracts (red-fleshed potatoes and radishes), the effect of pigment purity, and temperature were evaluated in model juices (pH 3.5). Color (CIELch) and anthocyanin degradation was monitored for 65 wks of storage. All model juices showed color similar to FD&C Red # 40. Excellent stability was obtained with all treatments in refrigeration. Anthocyanin structure and extraction method affected pigment stability. At 25°C, higher stability was obtained on juices colored with chemically purified radish anthocyanins (22 wk half-life) and lowest with potato vegetable juice (10 wk half-life). / Graduation date: 1999

Vacuum frying is a promising method for preserving the desired color, texture, and flavor of products with high sugar content. Since most vegetables and fruits degrade when processed with traditional frying, vacuum frying is an excellent alternative to high temperature processing. However, in vacuum frying the product should be pre-treated before frying to obtain a better texture. The kinetics of oil absorption and oil distribution in sweet potato chips (total, internal, and surface oil content) was studied so that effectiveness of the de-oiling system could be established. An analysis of product quality attributes (PQA) such as moisture content, oil content, microstructure, diameter shrinkage, and thickness expansion, as well as, color, texture, bulk density, true density, and porosity of chips fried at different temperatures (120, 130, and 140°C) was performed to evaluate the effect of process temperature on the product. The final oil content of the sweet potato chips was 0.178±0.007, 0.178±0.011, and 0.172±0.002 g/g solid for frying temperatures of 120, 130, and 140ºC, respectively. These values were lower (~60% less) than those found in traditionally fried sweet potato chip, which indicates that the de-oiling mechanism is crucial in vacuum frying processing. It was found that the rate of change in PQAs is greatly affected by temperature; however, the final values of bulk density, true density, porosity, diameter shrinkage, and thickness expansion were not affected by temperature. The texture of the samples was affected by temperature, with the chips fried at 140 degrees C being crispier. In terms of color, the L* and color b* values decreased as temperature increased. While color a* was not affected by temperature. In this study, a two-stage frying process was also evaluated to improve the flavor and texture of sweet potato chips. First, a basket filled with the sweet potato slices was submerged into the oil under atmospheric conditions. As soon as the potato slices were partially cooked (1 min), the pressure was lowered to 1.33 kPa (vacuum frying stage) and the product fried for 2 more min. The products were fried at 130 degrees C for different interval of times. Starch gelatinization, texture, moisture content, and oil content were evaluated at each time interval. Sensory analysis was accomplished by using a consumer panel with 50 members. The samples were compared with the on-stage frying and atmospheric frying processes. The two-stage fried chips had better appearance and texture compared to the ones that were only fried under vacuum or atmospheric conditions. The samples were lighter and more yellow than the chips fried under the single-stage process. In vacuum frying, the temperature of the chips does not reach the gelatinization temperature until most of the water is evaporated. Therefore, there is not sufficient moisture content in the product for gelatinization to occur completely. As a result, the product has a glassy texture. In the two stage frying, the atmospheric frying prior to vacuum frying helps the starch to gelatinize thus producing a better product in terms of texture, oil content, and flavor. The atmospheric fried samples were darker in color and had a scorch taste. The degree of starch gelatinization was 21% higher for the two-stage fried samples than the single-stage fried ones. The application of the dual stage enhances the quality of sweet potato chips, improves consumer satisfaction, and reduces the need for space, cost, and any other needs of blanching pre-treatment to the sweet potato manufacturers.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 405-414). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 405-414). Also available on the Internet.

Orientador: Neuza Jorge / Banca: Odair Zenebon / Banca: Ana Lúcia Barretto Penna / Resumo: O mercado de chips e snacks, particularmente àqueles obtidos de matéria-primas ricas em amido como banana, mandioca e mandioquinha-salsa, embora não suprem as necessidades diárias do indivíduo, vem ocupando um espaço cada vez maior, especialmente nos centros urbanos. O objetivo deste trabalho foi avaliar a composição nutricional, o perfil de ácidos graxos e as informações nutricionais dos rótulos das amostras de batatas chips e de snacks extrusados. Foram coletadas 10 amostras de batatas chips e 10 amostras de snacks extrusados, obtidas de três lotes diferentes. A análise nutricional, realizada pelos métodos oficiais, constou das determinações de umidade, proteínas, lipídios, cinzas, carboidratos totais, valor energético e sódio, calculado a partir do cloreto de sódio. O perfil de ácidos graxos obtido por cromatografia gasosa, sendo os picos identificados por tempos de retenção com padrões de ésteres metílicos e os resultados calculados e expressos g/100g da amostra. As informações nutricionais dos rótulos de ambos os produtos foram avaliados de acordo com as Resoluções RDC 359/03 e RDC 360/03. análise estatísticas dos resultados indicou que as interações entre marcas e lotes foram significativas para todas as determinações da composição nutricional, tanto as batatas chips como para os snacks extrusados. Os teores de sódio encontrados oscilaram entre 120 a 688 mg/100g para as batatas chips e 372 a 1.328 100g para os snacks extrusados. Os perfis de ácidos graxos determinados nas batatas chips e nos snacks extrusados provenientes de diferentes marcas foram, em média, 39,28 e 22,36% para ácidos graxos saturados, 39,75 e 10,69% para monoinsaturados, 18,62 e 38,18% para poliinsaturados e, 2,34 e 28,78% para trans, respectivamente. Quanto as informações nutricionais dos rótulos, os erros relacionados aos itens obrigatórios mais encontrados... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Junk foods like chips and snacks, which are starches' sources of raw material, for example, banana, cassava and mandioquinha-salsa, don't enhance the daily necessity of diary's individuals, but are lots of consume in large urban centre. The aim of this study was evaluate the nutritional composition, the profile of fatty acids and the label information of samples of potato chips and extruded snacks. It was collected 10 samples of potato chips and extruded snacks from 10 samples, obtained from three different batches. The nutritional analysis was determined by official methods consisted of the determination of moisture, proteins, lipids, ash, total carbohydrates and energy. The analysis of sodium was performed using the determination of sodium chloride. The profile of fatty acids was obtained by gas chromatography and the peaks identified by retention time with standards of methyl esters and the results calculated and expressed as g/100g of the sample. The labels information of both of the products was evaluated according to the DRC 359/03 and 360/03 Resolutions. The statistics' analysis of the results indicated that the interactions between brands and batches were significant for all determinations of nutritional composition, as for potato chips as for extruded snacks. The sodium levels ranged from 120 to 688 mg/100g for potato chips and from 372 to 1328 mg/100g for extruded snacks. The profiles of fatty acids presented by the potato chips and extruded snacks from different brands were on average 39.28 and 22.36% for saturated fatty acids, 39.75 and 10.69% for monounsaturated, 18.62 and 38.18% for polyunsaturated, and 2.34 and 28.78% for trans, respectively. As label information, the mistakes (errors) related to the compulsory items were on the conversion to kJ, compulsory declaration and declaration of nutrients per serving, for both products. As for the mistakes (errors)... (Complete abstract click electronic access below) / Mestre

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