Band 3, Heft 5

The physical properties of fibered flaxseed were investigated within moisture content varying from 6.21 to 16.29%. The length, width, thickness and geometric mean diameter increased from 4.20 to 4.44mm, 1.99 to 2.13mm, 0.91 to 0.95mm, and 1.95 to 2.06mm, respectively in the moisture content range. One thousand seed weight increased linearly from 4.22 to 4.62g. The bulk density decreased from 726.783 to 611.872kg/m3, while the true density increased from 1165.265 to 1289.341kg/m3 in the moisture content range. The porosity values of flaxseed increased linearly from 37.67 to 52.54%. The highest static coefficient of friction was found on the plywood surface, while the lowest on the stainless steel surface. The static coefficient of friction increased from 0.467 to 0.972, 0.442 to 0.864, 0.492 to 0.927, and 0.490 to 0.845 for plywood, stainless steel, aluminum sheet and galvanized iron, respectively. The angle of repose increased linearly from 25.7° to 33.8° in the moisture content range. The results are necessary for design of equipment to handling, transportation, processing, and the storage of flaxseed.

The application of mixed cultures of lactic acid bacteria (LAB) and yeasts in the baking process may improve a number of important properties of the final bakery products such as flavour, texture and retention of freshness compare to the traditional baker's yeast bread. This study offers the possibility for Brazilian bakers to improve the quality of their products. The methods of sponge-dough and direct-dough fermentation containing Lactobacillus brevis and yeast Saccharomyces cerevisiae were employed to verify the effect of mixed cultures in quality technology of sweet bread dough. According to the results, performance of the breads should be good, because the used flour forms a strong gluten network, retains gas and produces a highly expanded structure in the final bakery products. Sensorial evaluation demonstrated that sweet bread produced by sponge-dough fermentation was more acceptable in regard to softness and taste compared to bread produced by direct-dough fermentation.

A single tube, stainless steel, liquid desiccant falling film evaporator was built and tested with the calcium chloride solution as the liquid desiccant to concentrate liquid foods. Experiments were conducted in the above setup with sugar solutions as the liquid food. To minimize water vapor mass transfer resistance, non-condensibles were removed from the system by a vacuum pump. No steam was used to drive this evaporator.The liquid food was heated to about 48ºC when the ambient temperature was 40ºC. The single tube double falling film evaporator was tested to determine the effect of desiccant concentration, temperature, and flow rate on the evaporation rate. The effect of liquid food concentration, temperature, and flow rate on evaporation rate was also studied. An uncertainty and error analysis for the experimental data was performed. It was demonstrated that liquid desiccants could provide enough energy, through heat of absorption, to evaporate a liquid food in a falling film evaporator with vapor transfer lines.

The adsorption characteristics of anthocyanins from purple-fleshed potatoes on 11 macroporous SDVB, acrylic and methacrylic resins were investigated. Anthocyanins were first extracted from purple-fleshed potatoes using dilute acid solutions, and then partially purified by membrane filtration, which resulted in the removal of more than 90% of the total sugar and proteins from the crude extract. The partially purified extract were mixed with the resins at varying extract/resin ratios until equilibrium adsorption was reached and the adsorption data were fitted to the Langmuir and Freundlich isotherms. Both models were found suitable to describe the adsorption isotherms of anthocyanins on the resins tested. Adsorption capacities for anthocyanins increased with the rise of temperature for SDVB resins but decreased for metharcylic resins. The resin with the highest adsorption capacity for anthocyanins was XAD-1600, on which anthocyanin adsorption was an endothermic process and favored at higher temperature.

Since commercial colorimeters measure small area with a fixed geometry, the result of color measurement is usually unrepresentative for heterogeneous materials as in many food items. This paper describes a computer vision based approach for the measurement of color in a user defined polygonal area on the digital image of a food product. The algorithm used for color measurement converts the RGB values of the image captured by a digital camera to monitor L*a*b* values using the standard equations. The RGB responses for a captured image vary from one case to another, so, the direct transformation from RGB to L*a*b is not useful to obtain meaningful information about the color. Here, an artificial neural network (ANN) model was used to convert the monitor L*a*b* values into spectrophotometric L*a*b* values. The ANN model was calibrated by using the IT8 color chart consisting of 288 different colored squares which reflect all possible variations in the color space. The ?E values for the estimated values and the real spectrophotometric values were less than 0.45.

This paper proposes the liquid inertia coupled to the dynamics of micro bubbles as one of the mechanisms for microbe inactivation by high pressures. Liquid inertia can cause a stable bubble to grow unlimited through a pressurization followed by a sudden pressure release. In cases when the vapor pressure is too low to allow unlimited bubble growth, the liquid inertia leads to the hammering effect associated with nonlinear bubble oscillations, a purely mechanical effect that may be responsible for microbe inactivation.

The use of thawed raw material is becoming more frequent in the cured ham processing industry. At the same time, the incidence of PSE meat in the raw material can be very important. The aim of this work was to characterise the salting and post-salting stages of PSE thawed hams, and to study the influence of process and product variables on the results obtained in industry. A deeper knowledge of this influence could help reduce the variability in salt concentration obtained in the process. Findings indicate a strong influence of pH, total ham weight, Lean/Fat ratio and the contact area of the hams in the salting stage, while the post-salting time was the variable that exerted the greatest influence on the salt and water distribution inside the hams during this stage.

White onions were dried using an osmo-convective drying technique. Osmotic dehydration was done by dipping the onion slices in 10, 15 and 20 brix NaCl solution at ambient temperature for one hour. The increase in the concentration of NaCl increased the water loss, solid gain and weight reduction in onion slices. The drying times of pre-osmosed onions slices at drying air temperature of 50, 60 and 70°C were 6.75, 6.00 and 5.25 h respectively. The moisture diffusivity increased with increase in air temperature and ranged between 0.83 and 0.91x10-10 m2/s. Quality of dried product in respect to flavour strength and color was superior. A lowest specific energy consumption of about 1.98 kWh/kg was found in the air drying of onions pre-treated with 20 brix NaCl solution and at air temperature of 70°C.

Moisture sorption isotherms of osmotically dehydrated sweet peppers were determined at 15oC, 30oC and 40oC using static desiccator techniques. In the study, seven levels of water activity in range of 0.08 to 0.91 were used by the use of saturated salt solutions. The isotherms were found to be sigmoid type and of BET classification II. Out of seven sorption models i.e. BET, modified BET, Hasley, Caurie, GAB, Oswin and Smith, fitted to the experimental data, Oswin model was found to be the best for accurate prediction of moisture sorption isotherm with highest value of coefficient of determination (R2) and lowest values of standard error (SE) and relative deviation parentage (Rd). The value of monolayer moisture content of the osmotically dehydrated sweet pepper was found to be 3.037%, 3.934% and 4.432% (db) at 15oC, 30oC and 40oC respectively. The values of net isosteric heat of sorption as calculated by Clausius–Clapeyron equation showed a regular fall with increase in moisture content.

Cooling of fresh produce inside ventilated packaging is one of the important postharvest operations to maintain the coolchain of horticultural produce. In two recent articles, we described the development of CFD-based mathematical models for thermodynamic design of ventilated packaging systems and presented the results obtained from model testing based on fresh apples undergoing rapid cooling inside layered cartons, pallets of cartons, and bulk bins. In the current article, we present the results of a sensitivity analysis of the modeling system under refrigerated air cooling of apples inside a carton used in the horticultural industry. Sensitivity tests showed that inaccurate input value of the inlet air velocity within 10% would contribute to inaccuracy of about 0.5 ºK in the model predictions, which is within the measurement error of most temperature measuring devices used in the postharvest industry. Variations in vent areas on both front and back walls of the package within ±20% did not significantly alter the model predictions in the near-inlet region, but had noticeable effects at the package centre and near-outlet regions. Altering the position of vents did alter the heat transfer between air and packaged produce, presumably by changing the airflow distribution among the layers of produce inside the package. Sensitivity of the model to changes in the gap between the trays and package walls highlights the importance of gentle handling of packages to minimize lateral movement of trays and fruit prior to stacking for precooling and long-term cold storage.

In this study, some engineering properties of cassava tuber samples were determined experimentally under five moisture content levels of 70 %, 65 %, 60%, 55 %, and 50 %wet basis. The properties measured were tensile strength, compressive strength and elasticity. Three experimental tools were designed and fabricated using spring balance, hose-clips, and 12Volts motor with reels and rope for the investigations. The IITA improved cassava variety TMS 4(2) 1425 was used in the experiments. Results of the tests indicated that all the properties measured were influenced by the moisture contents of the tuber.

Based on a three level Box Behnken design involving the variables pH (X1), incubation temperature (X2) and fermentation time (X3), a response surface methodology for the production of carotenoid by a mutant Aspergillus carbonarius CFTRI-UV10046 was standardized. Data analyzed using a second order polynomial equation resulted in the optimized process condition of 46.7 h growth at 29.30C in a corn flour medium of pH 3.3 for carotenoid production. Under these conditions the model predicted 1283.00 µg of carotenoid /g of dry fungal biomass which is 52.19% higher then the initial medium. With regard to biomass, 2.44 g dry weight/100 ml culture medium was obtained after 56 h of growth at 29.70C in the medium of pH-3.6.

This study was conducted to assess in detail the possible effects of some technological processes such as soaking, germination, cooking, soaking + cooking, and germination + cooking on the lipid composition of mung bean seeds of Giza 1 variety. TLC analysis of mung bean lipids showed that the phospholipids and triglycerides recorded the highest percentage among lipid fractions (32.26 and 30.10%), while the 1,3 diglycerides constituted the least percentage (2.80%) in mung bean seeds. The soaking, germination and cooking processes caused a decrease in the phospholipids, triglycerides and hydrocarbons accompanied with an increase in monoglycerides, 1,2-(2,3)-diglycerides, sterols and free fatty acids. Eleven fractions were separated from phospholipids class of the studied samples; seven of these fractions were identified. The major component of phospholipids was phosphatidyl choline, amounting to 21.30, 17.84, 16.21, 13.87, 13.20 and 11.47% of the total phospholipids in raw, soaked, germinated, raw-cooked, soaked-cooked and germinated-cooked mung bean seeds, respectively. Gas liquid chromatography of the total lipids of mung bean seeds showed that the unsaturated fatty acids represented 69.58, 64.35, 63.3, 63.16, 61.84 and 61.12%, while the levels of saturated fatty acids were low being 30.37, 34.05, 35.66, 34.64, 37.93 and 38.75% of the total fatty acids in raw, soaked, germinated, raw-cooked, soaked-cooked and germinated-cooked, respectively. The total essential fatty acids (linoleic and linolenic) represented the highest proportion of fatty acids (50.10% of the total fatty acids).

Moisture sorption isotherms of Granny Smith apples hot-air dried and texturized by Controlled Sudden Decompression (Détente Instantannée Contrôlée DIC®) were determined and compared using a gravimetric method. The DIC has been developed to confer a porous structure to partially dehydrated foods by expanding them and facilitating the drying process at lower water content. The samples were stored in a chamber; the relative humidity is controlled by an atomizing humidifier at 20, 30 and 40°C, and relative humidities ranging from 10% to 90%. The sorption capacity decreased with increasing temperature at a given water activity. The hysteresis effect was not significant for both of the dried and texturized apples. The experimental sorption data were fitted to 8 various isotherm models including two parameter relationships (BET, Halsey, Smith, Henderson, Oswin), three parameter equations (Ferro-Fontan, GAB) and four parameter equations (Peleg). A non-linear least square regression software was used to evaluate the model's constants. The goodness of fit of each isotherm was quantified through the mean relative percentage deviation modulus E. The Ferro-Fontan, Peleg, GAB and Oswin equations were best for characterizing the sorption behaviour of Granny Smith apples for a whole range of temperatures and water activities studied. The surface area corresponding to the monolayer was determined for the texturized apples and compared to the dried samples. The results showed that the treatment by DIC increases the surface area of apples. For understanding the water properties and calculating the energy requirements phenomena, net isosteric heat was evaluated by the applying Clausius-Clapeyron equation.

Several parameters related to the physicochemical properties of Josapine pineapple juice, such as moisture content, total soluble solids (TSS), pH, color, water activity, freezing point, sugar content and acidity, were evaluated over a week of ambient storage at 25oC and 52% RH. The results indicated that Josapine pineapples take about 11 days to progress from maturity stage 1 to stage 7. The moisture content of fruit increased from 93.5% wb to 95.1% wb over the 11 days period. Analysis on the color of the juice showed the color space coordinate parameter b varies between 9.11 to 15.8, parameter a increased from –3.33 to –3.68 and the 'L' value decreased from 39.46 to 38.7 at the initial ripening stage but increased to 40.9 in the later stages. The TSS increased at the early ripening stage but decreased toward the end of ripening period. Freezing point, water activity and pH of juice range were –2.77 to – 2.90 oC, 0.988 to 0.997 and 3.81 to 4.10 respectively. The total sugar and acidity in juice range were 12.5 to 17% and 0.69 to 0.90% respectively. The TSS/acid ratio of juice range was 12.32 to 18.60. The data presented in this work demonstrate the relationship between physicochemical properties of Josapine pineapples and the ripening process.

In this paper the texture profile analysis for the cooked Bori nuggets (traditional Indian food) prepared from black gram batter having different initial moisture content of 62 to 72% (wb) and air incorporation of 14.14 to 18.12% (v/v) is discussed. The initial moisture content and the volume of air incorporation into the batter had significant effect at either 5% or 1% level of significance on the springiness, chewiness, hardness, cohesiveness and gumminess of the cooked nuggets. The optimum initial moisture content of 65.10 to 67.15% (wb) in the batter and air incorporation of 15.91 to 17.23% (v/v) in it are recommended in obtaining the maximum and minimum levels of the response quality parameters. The optimum values of these response parameters would be 0.453, 12.22, 60.31 N, 0.36 and 22.36 for springiness, chewiness, hardness, cohesiveness, and gumminess, respectively.

Apple seeds, a common byproduct of apple processing, have been examined for their overall proximate composition, fatty acid and amino acid composition of the lipid and protein components, respectively, as well as their key mineral constituents. Proximate analysis indicated that apple seeds are rich in oil content and protein ranging from 27.5 to 28% and 33.8 to 34.5% respectively, comparing favorably with oilseeds. GC analysis indicated high levels of linoleic acid (~49%) with the other dominant fatty acids being oleic, palmitic and stearic acids, ranging from ~39, 7 and 2% respectively. Amino acid analysis indicates that there are substantial amounts of sulfur containing amino acids in the apple seed. The apple seeds also contain significant amounts of phosphorus, potassium, magnesium, calcium and iron, in the order of 720, 650, 510, 210 and 110 mg/100g, respectively. Based on the proximate composition of the apple seeds, if adequate amounts are available as a process byproduct, apple seeds could have value-added potential as a source of edible oil, with the oil cake potentially serving as an animal feed supplement.

Effects during thermal processing of entrapped air on lethal effect were evaluated in three domestic canners with quart mason jars. Entrapped air volumes in ceramic-bead products were established with various fillings of water into a dry product matrix. Lethal effects were determined using thermocouples positioned near the bottom, middle, and top of the model product and others outside the jars. Two canners (All American and Mirro models) were continuously vented during the process while the third (National Presto) was not — but was vented de facto until the lid lock moved up under the influence of escaping gases. Higher lethal effects were noted when least product-entrapped air was modeled.

Effects of entrapped air during thermal processing on lethal effect were evaluated in three domestic canners with quart mason jars. Entrapped air volumes in ceramic-bead products were established with various fillings of water into a dry matrix. Alternate periods of venting included 5, 10, and 15 mins. Process pressure was monitored throughout each of the 54 runs. Venting times and lack of continuous venting demonstrated little impact. Higher lethal effects were noted when the least product-entrapped air was modeled. Differences were noted between pressure processes monitored by the dial gauge versus the calibrated weighted-devices with more variation of the dial gauge system due to the manual control basis.