Band 4, Heft 2

For optimization of osmotic dehydration process of carrot cubes in sodium chloride solution by response surface methodology, the experiments were conducted according to Face-Centered Central Composite Design (CCF). The independent process variables for osmotic dehydration process were osmotic solution concentrations (5 -15% w/v sodium chloride), temperature (30 -50°C) and process durations (90 -150 minutes). The osmotic dehydration process was optimized for maximum water loss, minimum solute gain, maximum retention of colour and sensory score. The optimum conditions were 7.9 % sodium chloride concentration; 30°C osmotic solution temperature and 150 minutes process duration.

In this paper, the fatty acid composition of turkey meat sucuk (soudjuck), salami, and sausages were determined and compared with each other. The fatty acids methyl esters of each product were identified by capillary gas chromatography. Most of the fatty acids in sucuk (soudjuck) samples were monosaturated; however in salami and sausages samples most of were mono and di-unsaturated. Saturated fatty acids in sucuk (soudjuck) samples followed, having the palmitic and stearic acids as their major components and had a range of 229.7-385.2 g kg-1 and 87.6-215.9 g kg-1. In salami and sausages samples, unsaturated fatty acids, the oleic and linoleic acids were the major components and had a range of 170.0-542.0 g kg-1 and 151.5-353.0 g kg-1. PUFA (polyunsaturated fatty acids) were found for sausages in the highest amount with linoleic acids concentration. Turkey meat salami and sausages presented a higher content of unsaturated and polyunsaturated fatty acids than turkey meat sucuk (soudjuck).

Agitated vessels are often used for homogenization of the miscible liquids in chemical, biochemical, and food industries. Computational fluid dynamics (CFD) is a useful tool for studying fluid flows, including those of mixing systems. It is particularly powerful where the ability exists to corroborate model results with available data. The CFD simulation was carried out for Rushton and Smith turbines agitators. The standard k-? model has been used for turbulence modeling. The data obtained by simulation are matching with the literature experimental value for standard baffle with the discrepancy of less than +_4.5% for power number. The simulated results for agitated vessel with short baffle (non-standard) are agreeing with the literature values within plus or minus 5% for Power Number.

Insights into the relationship between the air relative humidity (water activity (aw)) and equilibrium moisture content of food materials is essential to maintain good keeping quality and optimize process operation. The adsorption isotherms for cassava flour (lafun) were investigated with the static gravimetric method. Concentrated acid (H2SO4) solutions were used to vary the micro-climate in the study and presented in an easy-to-use template-like format over the range of temperature (27- 40oC) and aw (0.10-0.80) usually experienced in the tropical environment. The experimental data were compared with five widely recommended models in the literature for food sorption isotherms (GAB, modified GAB, modified Oswin, modified Henderson & modified Chung-Pfost). The moisture sorption isotherms were sigmoidal in shape and were influenced by temperature. The modified Oswin model was found to be most adequate whilst the modified GAB appears not suitable to model the adsorption isotherms for lafun.

Processing cassava onto pellets, an internationally acceptable and commercially rewarding cassava product minimizes quantitative and qualitative losses. Pellet samples were produced through the conventional chipping, drying, milling then pelleting with and without steaming (CDMP-S and CDMP) and modified process of grating, dewatering then pelleting and steaming (GDWP-S). Investigations for storageability, durability, uniformity in dimension and nutritional qualities resulted in pellets with moisture content of 9%, uniformly light brown in colour, free from objectionable odour with no sign of deterioration after 90 days of storage. The durability index and fine formations are 99.8% and 0.2%, 98.8% and 1.2%, 99.4% and 0.6% for CDMP-S, CDMP and GDWP-S respectively. The average lengths of 2.81, 2.23 and 2.74 cm and diameters 0.76, 0.73 and 0.67 cm respectively fall within the standard. The carbohydrate contents are 82.9%, 83.4% and 84.5% and cyanogenic glycosides contents of 14.18mg/100g, 14.32mg/100g and 10.13mg/100g respectively. The pellets produced from the modified process GDWP-S in addition to satisfying the standard colour code also conforms favourably well in terms of strength, durability and nutritional quality with the conventional CDMP-S and are better than the cold pellets from the conventional process CDMP. These are in addition to the reduction of about eight hours of chip drying operation in the modified process. This reduction in time and energy with associated quality products show that the modified process is a promising approach in the production of pellets acceptable in the export market.

In this article, a mathematical model was developed for the numerical simulation of the water diffusion in an infinite cylinder. A solver for the diffusion equation was created using the finite volume method, with a fully implicit formulation. In order to create such solver, it was assumed that the boundary condition of the first type is adequate to simulate the physical problem. The solver presupposes variable thermophysical properties and radius in the domain. In order to determine the parameters of the expression between the diffusivity and the moisture content, an optimizer was created, based on the inverse method. The developed mathematical model was applied to simulate the drying of banana and rough rice, using experimental data obtained from the literature. The results obtained in this article, considering the variable diffusivity, are better than the results obtained originally in the literature, where the water diffusivity was considered constant.

Effect of air temperature (50, 60 and 70 °C) and sample thickness (1.0, 1.4 and 1.8 mm) on the thin-layer drying characteristics of eriste was studied by using a tray dryer. The data of sample weight, dry and wet-bulb temperatures were recorded continuously during each experiment and drying curves were obtained. The drying curves were then fitted to five mathematical models available in the literature to estimate a suitable model for drying of eriste. Verma et al. model gave better predictions than other models and satisfactorily described the thin layer characteristics of eriste. The effective diffusivity varied from 1.8 x exp-10 to 1.5 x exp-9 m2 s-1 over the temperature range.

Protein concentrates were prepared from defatted rice bran at different extraction temperature (30-75°C) and analyzed for their functional properties. Protein yield increased as the temperature of extraction was increased while the protein content of protein concentrate decreased. Water binding capacity was in the range of 1.1-2.27 g/g while oil absorption capacity ranged between 1.64 and 6.89 (g/g). RBPC extracted at 60°C exhibited maximum foam producing capacity of 120% at 1% salt concentration. Emulsifying capacity of protein concentrates ranged between 33.71-70.85%. Emulsion capacity decreased as the temperature of extraction was increased. Emulsions were fairly stable under different pH, salt and sugar concentrations.

Fuzzy supervisory control scheme for regulating the tank pressure in a pilot pressure control system has been presented. The controller structure has been designed in such a way as to adjust on-line the parameters of a classical PI controller that will reduce the human involvement in tuning the controller parameters at different operating conditions. The control algorithm for the proposed scheme has been developed using KEIL software and then converted into an executable file before downloading it to an ARM7 (AT91M55800A) based embedded target board. The pipeline execution and RISC architecture of ARM7 target board enhances the computation speed in real time control applications. Experimental study has been carried out to test the performance of the proposed supervisory fuzzy controller and the results were compared with classical control method. Better control performance using supervisory fuzzy controller has been obtained.

?- Linolenic acid (GLA) is an intracellular primary metabolite produced by some plants and fungal species via several distinct biosynthetic pathways. It is an essential fatty acid, and is mainly used in treatment of various diseases such as rheumatoid arthritis, multiple sclerosis, schizophrenia, atopic eczema and premenstrual syndrome. It is also a precursor of a number of biologically active compounds. In present work, strains of Cunninghamella echinulata var.elegans MTCC 552, Mucor rouxii MTCC 386, Mucor hiemallis MTCC 1278 and Rhizopus stolnifer MTCC 2591 were screened for maximum production of GLA. Cunninghamella echinulata var. elegans MTCC 552 produced maximum GLA (13.7 ± 0.31 mg/g of DCW), and hence selected for further work. Many crucial factors that affect GLA production were optimized in two steps. In the first step, one factor at a time method was used to investigate the effects of media constituents. Subsequently, in the second step, concentration of media components was optimized using Response Surface Methodology (RSM). These optimizations increased the GLA production to 19.8 ± 0.35 mg/g of DCW.

The strawberry culture in Morocco knew a fast development since the first tests of modern culture in the areas of favorable microclimates. This culture covers up to 20% of the cultures under shelter and is intended not only for local consumption and for the Moroccan agro-industrial sector but also for export to European countries. The strawberry is a fragile fruit which is degraded easily. Its high content of sugar allows for the development of the micro-organisms and the rate of rot of the fruit. In fact, it is of interest to develop and improve techniques of conservation in order to limit the post-harvest losses. In this work, an impact study of refrigeration combined with ionization was carried out with the aim of optimizing the shelf life of the strawberry without deteriorating its organoleptic qualities. A follow-up of the evolution of the mesoaerobes, yeasts, and moulds, as well as coliforms, was carried out for the ionized strawberries with various doses and preserved at 2 and 7 °C, with an aim of determining the best combination dose-temperature of storage for the strawberries.

Wet particles are often difficult to dry due to their stickiness and tendency to form lumps. Mechanical vibration can assist in separating such particles as well as in mixing beds of dissimilar particles if necessary. Delumping also exposes surfaces for evaporation. The objective of this experimental project is to design, build and test a laboratory size vibrated drum dryer under vacuum. The basic concept is to design a variable frequency, variable amplitude vibratory unit on which a horizontal drum is seated. An experimental approach was employed to permit simultaneous or individual mode of conduction and radiation heat input. Cube shaped potatoes and apples were used as model samples for experimental tests. Experiments were also performed using spherical shaped silica gel. Five different drying conditions were compared experimentally. These are: case-1, effect of vacuum; case-2, vacuum with vertical sinusoidal vibration (Amplitude: 0-5mm, frequency: 10-50 Hz); case-3, vacuum with vibration and conduction heat input (40C); case-4, vacuum with vibration and radiation heat input (1875 W/m2); case-5, vacuum using vibrating bed dryer with simultaneous conduction and radiation heat input. An energy savings strategy for drying is proposed based on the study. Results indicated that the proposed system is a variable option to reduce the process time under vacuum compared to other drying methods.

The degradation behavior of Silk Fibroin (SF) by elastase was investigated. The inhibitory effects of the hydrolyzed solution on ?-glucosidase were also examined. Elastase follows Michaelis–Menten kinetics with Km and Vm values of 14.49 mg/ml and 1.96 ?mol/min, respectively, and the SF peptides with Km and Ki values of 3.8 mg/ml and 3.55 mg/ml. The inhibition effect of the peptide solution on ?-glucosidase was found to be noncompetitive and reversible. The hydrolyzed fragments with molecular weights under 6 kDa exerted the prominent inhibiting effect on mice ?-glucosidase, with the inhibition activity of 36.6 – 38.9%. These results suggested that SF peptides might exert anti-diabetic effect by suppressing carbohydrate absorption from the intestine, and thereby decrease the postprandial increase of blood glucose.

Wine discrimination and analysis is typically done through chemical analysis and sensory evaluation by a trained panel. Both of these methods are proven to be successful in wine discrimination, but require extensive preparation, time and money. The electronic nose is an objective, rapid-analysis tool that has been used in the food industry for a number of applications. The purpose of this study was to determine if an electronic nose can accurately discriminate between Cabernet Sauvignon (Vitis vinifera L.) wines made from grapes that have received different pre-harvest but post-bloom spray treatments to enhance growth.Aqueous ethanol, which has been shown to impact fruit maturity, was sprayed on the grape clusters at 13 weeks post bloom in different concentrations (control, 5% and 10% v/v). Chemical analysis was able to accurately discriminate between the wines produced from these grapes. Triangle difference testing by a consumer panel was not able to differentiate between the different treatments. The electronic nose data was able to accurately identify the control group and the 5% EtOH treatment 90% of the time. Placement of the 10% EtOH group was only 13% correct. The results show the promising potential for an electronic nose to discriminate between control and treated wine samples.

Presently in China de-shelling of chestnuts is done manually, which is tedious, time consuming and labor intensive. The de-shelling operation has become the greatest problem and poses a bottleneck to the chestnut processing industry in China. To overcome this problem, the objective of this study is to derive optimum conditions for chestnut de-shelling using air-impingement de-shelling technology. Response surface methodology was employed to analyze the effects of air temperature (163-197oC), processing time (109-311s) and air velocity (6.68-9.73m/s) on the rate of water loss, de-shelling rate and lightness. Prediction models were also established. Optimum conditions obtained were 179oC of air temperature, 278s of processing time and 7.83m/s of air velocity. Values predicted by the models for the water loss, de-shelling rate and lightness under optimized conditions are 4.14%, 86.95% and 58.65, respectively. The experimental data fit well with the predicted values.