A batch vacuum frying system, which processes fruits and vegetables, includes a frying pan, a surface-condenser, and a vacuum pump. With health and safety issues in mind, this research focused on developing a modified surface-condenser to prevent cavitation of the vacuum pump. The final oil-content was reduced by centrifugal de- oiling of the product under vacuum, which make the product healthier than what is currently available. The de-oiling mechanism consists of a centrifuge with a motor attached to the basket shaft, rotating up to 750 rpm (63 g units). The condenser consists of a (counter- flow) spiral-coil heat exchanger (SHE) connected to a refrigeration system that uses R404a refrigerant. De-oiling for 40 s at 300 and 750 RPM removed up to 67% and 72% of the chip’s surface oil, respectively. At 750 RPM for 10 s, 40 s, and 60 s the oil-content was reduced by 38%, 44%, and 51%, respectively. The convective heat transfer coefficient (h) of the frying oil was determined at 120°C and 140°C using the lumped capacitance method. The h-values were 217±13 W/m2K (120°C) and 258±37 W/m2K (140°C) using a copper-ball thermocouple. The h- values increased to 3.6 times during the boiling period. COMSOLTM Multiphysics was used to model the heat transfer in the vacuum fryer pan. Based on the simulation results, a 1.5 cm thick insulation material was installed in the fryer to reduce the energy losses. The refrigeration system operates at Tevap = -26°C and Tcond = 50°C with 26°C sub-cooling. Sensitivity analysis showed that the system Coefficient of Performance (COP) was about 3.87 at these conditions and compressor power requirement (CPR) was 74 W (85% efficiency) when frying 30 g of potatoes slices. The best results were obtained at Tevap = -10°C and Tcond = 40°C with 26°C sub-cooling and superheat of 5°C. The predicted COP was 4 and the CPR 70 W. The ice-formation on coils reduced the condensation rate. Reducing the refrigerant temperature to -10°C (from -26°C) reduced the condensation rate by 30%. These results show a more effective vacuum frying system for high-quality fruits and vegetables than the system previously used.

Jerusalem artichoke has been cultivated in various regions without any special breeding technique. On the other hand, in food industry it does not have a wide usage area. Hence, in food industry its use as a potato substitute in some products is believed to be increasing its economical value. As a first attempt chips and crisps produced from Jerusalem artichoke was analyzed for texture, sensory, color, oil and moisture content. Jerusalem artichoke chips were fried in a bench top deep fat fryer for 120s, 180s and 240s at 160&deg / C, 170&deg / C, 180&deg / C and 190&deg / C. When microwave oven was used samples were cooked for 60s, 75s, 90s, 105s, 120s, 135s and 150s at 600 Watt and 900 Watt. Rheological properties of Jerusalem artichoke puree were investigated and Xanthan gum (2%wb) and sodium metabisulphite (1%wb) added for the desired puree consistence and color. After the production of puree Jerusalem artichoke flour was produced and water added to this flour then dough obtained again. Rheological behaviour of the original puree and these prepared from the containing 1- 4.5 and 1 - 5.0 part water were quite similar. In the light of the experimental results obtained as frying temperature and treatment time increased, moisture content and lightness of the Jerusalem artichoke products have decreased but a*and b* values, hardness, fracture and oil content increased. The best results for frying of Jerusalem artichoke seem to be 180&deg / C with about 240s treatment time for the chips and the same temperature for 180s for the crisps. As microwave power level and duration of treatment increased, moisture content and lightness of the microwave cooked Jerusalem artichoke products have decreased, but a* and b* values increased. Hardness and fracturability values of the products first increased with time and then decreased. When microwave oven was used, the best results were obtained for about 105s treatment time at 600W for the Jerusalem artichoke chips and about 60s processing time at 900W for the crisp. Since treatment time for cooking was significantly reduced when microwave cooking was used, this method could be recommended as an alternative to conventional deep fat frying, as oil is not used as well.

The formation of heterocyclic amines (HAs) have been proven to be carcinogenic and mutagenic and these compounds have been found in cooked food such as meat, poultry, and fish. There are strong relationships between potential cancer development and HAs through intake of the cooked food. / The yield of HAs along with the influence of fat content and soy protein on the formation of HAs were determined during heating (as in cooking) at different temperatures using the kinetic modeling approach. The formation of HAs is dependent on temperature, time, fat content, and soy protein. The increase of fat content in samples resulted in a lower concentration of HAs' concentrations and a lower activation energy of reaction. Fat apparently enhanced the formation of HAs in meats but diluted availability of precursors for reactions. An increase in soy protein concentration decreased the maximum concentration of HAs formed in the different cooking conditions. / Two different approaches were used in order to model the formation of HAs. First, an artificial neural network (ANN) was used with two data sets to train and test the ANN. An ANN consisting of 18 processing elements and two hidden layers showed the best performance for predicting the formation of HAs. Second, the formation of HAs were predicted using temperature profiles in a cooked sample during pan-frying. The temperature profiles in cooked meat patty were predicted using finite element method. The concentration of HAs depended on the meat patty's surface temperature developed during pan frying. The result of this study can be used to develop methods to reduce HAs in food thus optimize product quality and safety.

Sinapic acid derivatives and tocopherols in refining byproducts of commercially produced expeller-pressed canola oils were characterized and isolated. Additionally, the antioxidant activities of the phenolics were examined by three systems including an in vitro non-biological related assay, a cellular assay and a deep-fat frying model. Sinapic acid (SA： 42.9 µg/g), Sinapine (SP: 199 µg/g), and Canolol (CAN: 344 µg/g) were found in different byproducts of canola oil refining, namely, soapstock, spent bleaching clay, and wash-water, respectively. Tocopherols (3.75 mg/g) and other non-identified phenolic compounds (2.7 mg /g) were found in deodistillates (DDL). CAN and DDL revealed significant protection effect (p<0.05) against hydrogen peroxide induced oxidation in two mammalian cell lines. The results of deep-fat frying studies indicated positive effects of CAN and DDL in preventing lipid oxidation. The canola oils fortified with DDL and CAN showed a considerable reduction (p < 0.05) in oxidation products of lipid after frying.

The main objective of this study was to evaluate the effects of different flour and protein types on quality of deep-fat fried chicken nuggets. Additionally, the rheological properties of batters were studied and the batter viscosity was correlated with fried product quality. In the first part of the study, the effects of soy and rice flour (5%) addition to the batter formulation on product quality were studied. Coating pick-up of batters, and moisture content, oil content, texture, color, volume, porosity, and cooking yield of nuggets were determined for 3, 6, 9 and 12 minutes of frying times at 180&ordm / C. In the second part of the study, the effects of protein types (soy protein isolate, whey protein isolate and egg albumen) at different concentrations (1 and 3%) on quality attributes were studied. A batter formulation with no flour or protein addition was used as control. In both parts of the study, flow behavior of batters prepared using different flour and protein types were determined. Soy flour and soy protein isolate (SPI) provided the highest apparent viscosity. Batter viscosity was found to be correlated with coating pick-up. All batters were found to show thixotropic behavior. The batters were modeled as power-law fluid and all of them turned out to be shear-thinning except egg albumen added batter, which was shear-thickening. As a result of the study, among the flour and protein types used, 3% whey protein isolate (WPI) was found to be the most effective ingredient on improving quality parameters of deep-fat fried chicken nuggets. 3% WPI added batters provided the hardest and crunchiest product with the darkest color. It also reduced the oil content of fried nuggets significantly. However, low cooking yield values were observed for batters with 3% WPI. On the other hand, soy flour containing batters provided high cooking yield. Therefore, if high cooking yield with low oil content is desired, soy flour can be advised to be used in batter formulations for chicken nuggets.

The main objective of the study was to evaluate the effects of starch and gum types on product quality of deep-fat fried carrot slices. It was also aimed to evaluate the applicability of image processing for determination of oil uptake. In the first part of the study, carrot slices were dipped into batters containing three different concentrations of dextrin or pre-gelatinized tapioca starch and fried for 2, 3, and 4 minutes at 170&plusmn / 2 oC. Coating pick-up of batter formulations and moisture content, oil content, frying yield, bulk density, porosity, texture and color of fried slices were evaluated. In the second part of the study, the effects of different gum types (HPMC, xanthan gum, guar gum, guar-xanthan gum combination) on quality attributes were studied. No starch or gum added coating formulation was used as the control. Finally, images of carrot and batter sections of the fried samples were obtained using digital camera and area fractions of oil droplets were determined using image processing. Acceptable product quality was obtained at higher concentrations of pre-gelatinized tapioca starch. On the other hand, increasing dextrin concentrations had an adverse affect on the product quality. As a result of the study, guar-xanthan gum combination has been found as the most effective additive on the batter performance. This additive provided the highest moisture content, lowest oil content, highest volume and lightest color to the product after frying. The porous and crunchy structure obtained using this combination was at the acceptable level for deep-fat fried products. Determination of area fraction of oil droplets on carrot and batter surfaces of fried samples using image processing was correlated with the oil content of fried product at initial stages of frying. The correlation coefficient between moisture content and frying yield was found as 0.90. A correlation was also determined between oil content and moisture content (r= -0.88).

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2004. / Härtill 4 uppsatser.

p. 1-86 / Submitted by Santiago Fabio (fabio.ssantiago@hotmail.com) on 2013-04-10T18:03:14Z No. of bitstreams: 1 Rose Mary Dissertacao seg.pdf: 1283678 bytes, checksum: df940fdf0b264bb0637524a157985304 (MD5) / Approved for entry into archive by Rodrigo Meirelles(rodrigomei@ufba.br) on 2013-04-13T20:11:26Z (GMT) No. of bitstreams: 1 Rose Mary Dissertacao seg.pdf: 1283678 bytes, checksum: df940fdf0b264bb0637524a157985304 (MD5) / Made available in DSpace on 2013-04-13T20:11:26Z (GMT). No. of bitstreams: 1 Rose Mary Dissertacao seg.pdf: 1283678 bytes, checksum: df940fdf0b264bb0637524a157985304 (MD5) Previous issue date: 2008 / O objetivo deste estudo foi avaliar a eficácia de açõeseducativas na melhoria do processo de fritura por imersão em bares, lanchonetes e restaurantes da cidade do Salvador.Trata-se de um estudo de intervenção,randomizado, duplo cego, realizado no período de dezembro de 2006 a julho de 2007. Desenvolveu-se uma ação educativa com duração de três horas com funcionários e/ou proprietários dos estabelecimentos e distribuição de material educativo. Para avaliar a intervenção, foram analisados dados provenientes de três instrumentos de investigação: 1. Pré e pós-teste utilizados na capacitação de funcionários e/ou proprietários; 2. Questionário aplicado para avaliar as técnicas de fritura e infraestrutura disponível; 3.Análises de compostos polares totais (%), ácidos graxos livres (%),índice de peróxido(meq/kg) e índice de refração (40 ºC), para determinação da qualidade do óleo. Os resultados apresentam um melhor desempenho do grupo intervenção em comparação ao grupo controle. Comprovar que uma intervenção simples pode aumentar o nível de conhecimento dos funcionários e proprietários de estabelecimentos comerciais foi uma conclusão importante; no entanto, pode ter seu alcance limitado quando investimentos nas condições de trabalho não forem efetivados. / Salvador

Biodiesel is now considered as an important option for full or partial diesel fossil replacement. At the same time, biodiesel is a renewable and an environmentally friendly fuel. This work has as goal to employ residual vegetable oils for biodiesel production and evaluate its viability as raw material. For that, some initial steps were considered in order to get a correct planning for the project: i) gathering and purification of the raw material; ii) determination of the physico-chemical properties of the residual oils; iii) choice of the catalytic system based on the quality of the raw material; iv) biodiesel production; and v) evaluation of the properties of the biofuel produced. The results of the frying oils characterization are in agreement with the requirements, not compromising their use for obtaining biodiesel. The biodiesel production was conducted by basic and acid catalysis in the presence of methanol or ethanol, as alcoholysis agents. The best results, in biodiesel production, were obtained for methanolysis conducted in the presence of basic catalyst. The results presented here show a concrete possibility of the use of frying oil as raw material for obtaining biodiesel, even if the sample has been collected in small establishments. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O biodiesel constitui, nos dias atuais, uma importante alternativa de substituição para o diesel fóssil, sendo ao mesmo tempo um combustível renovável e ambientalmente correto. O presente trabalho teve como objetivo empregar resíduos de óleos comestíveis para a obtenção de biodiesel e avaliar sua viabilidade como matéria prima. Para tanto, algumas etapas foram realizadas: (i) coleta e purificação adequadas da matéria-prima; (ii) determinação das propriedades físico-químicas dos óleos residuais; (iii) escolha do sistema catalítico a ser empregado, em função da qualidade desses; (iv) obtenção do biodiesel; e (v) avaliação da propriedade desse biocombustível. Através dos resultados obtidos para os óleos de fritura foi possível constatar que os mesmos, de uma maneira geral, atendem às necessidades, não comprometendo sua utilização para obtenção de biodiesel. A obtenção de biodiesel foi conduzida por catálise básica e ácida, na presença de metanol ou etanol, como agentes de alcoólise. Os melhores resultados, em termos de rendimento em éster, foram obtidos para a metanólise conduzida em presença de catalisador básico. Os resultados aqui apresentados permitem visualizar uma possibilidade concreta da utilização de óleos de fritura como matéria-prima para a obtenção de biodiesel, mesmo que a coleta tenha sido realizada em pequenos estabelecimentos.

Master of Science / Food Science Institute - Animal Sciences & Industry / Fadi M. Aramouni / Sweet potatoes are a significant crop and are popular among consumers, particularly as french fries. Because the processing steps of making white potato french fries may be detrimental to the quality of a sweet potato fry, it is important to understand the impact of processing on quality and consumer acceptability. The variety of sweet potatoes can affect the texture, appearance, and consumer preference. Peeling processes have evolved from harsh lye treatments to more quick and efficient methods such as steam peeling. Blanching is one of the most important steps because it deactivates enzymes, including polyphenol oxidase and amylases, that affect texture and appearance. While hot water blanching is used by majority of french fry manufacturers, novel techniques like microwave blanching may be similarly effective and less detrimental to the texture and nutritional composition. Time and temperature of the blanching method can affect the texture and flavor by weakening cell walls and leaching sugars. Drying of sweet potato fries prepares the product prior to frying. Drying drives moisture off and allows the starch on the surface of the fries to gelatinize. Many types of dryers, including vacuum, hot air, and fluidized bed, have been evaluated for the rate of moisture loss and final product texture. Drying should not be done too quickly because case hardening will occur and make the product have a tough and chewy bite. Frying uses oil at elevated temperatures to develop color, flavor, and a crispy external texture. The type of oil, oil temperature, and time of frying will affect the finished product attributes. Low oil temperature may lead to higher oil uptake into the sweet potato fries. Vacuum frying compared to deep fat frying can create sweet potato fries with less darkening and less oil uptake, but this method would be difficult in large scale manufacturing. Opportunities in creating high quality sweet potato french fries are directly related to consumer acceptability and manufacturing capability.