Volume 10, Issue 1 -

Bioactive compound, namely piperine, was extracted from Sarawak black pepper using supercritical carbon dioxide extraction. Experiments were carried outin the range of 3,000–5,000 psi (20.7–34.4 MPa) pressures, 318–328 K temperatures, 0.4–1 mm mean particle sizes and5–10 ml/min carbon dioxide flow rates. Experimental data analysis shows that extraction yield ismainly influenced by pressure, particle size and coupled-interactions between these two variables. Extraction process was modeled accounting for intraparticle diffusion and external mass transfer. The kinetics parameters for the internal and external mass transfers were evaluated and estimated. Mass transfer correlation was also developed. From simulation results, good agreement between experimental and simulated data has been found.

Predictive functional control (PFC), a model predictive control algorithm, has been proven to be very successful in a wealth of industrial applications due to its many laudable attribute, such as its simplicity and intuitive appeal. For simple single input single output processes, PFC applications use a first-order plus delay internal model and, as long as such models improve the control over classical control strategies, then their use remains justified. In this paper, a higher order internal PFC model is considered in order to reduce any possible plant-model mismatch, where the internal model is formulated as a series of cascaded or parallel first-order systems. The control approach is compared to a more conventional over parameterized dynamical matrix control (DMC) approach, used extensively for Multi-Input Multi-Output systems in the petrochemical industry. This paper demonstrates the benefits of the PFC higher order formulation for a typical milk pasteurisation plant, with significant improvements in the variances of both controlled and manipulated variables when compared to a first-order PFC. In this aspect, the higher order controller competes well with DMC performances, however, using a much more simpler and compact internal model form.

Wheat is a staple food throughout the world. Sprouted wheat contains numerous vitamins, secondary plant ingredients, enzymes, mineral nutrients and trace materials. The present work was carried on drying of sprouted wheat ( Triticum aestvum ) in a laboratory fluidized bed using different operating conditions. Physical properties including bulk density, tapped density, particle density and porosity were determined for various forms of wheat. The proximate analysis and handling properties were measured. The entire drying period was considered to follow falling rate period. The experimental data were modeled using Fick’s diffusion equation and the effective diffusivity coefficients were found to be within the range of 7.3 × 10 –10 to 30.4 × 10 –10 m 2 /s. Malting caused significant increase in protein content. During drying lightness increased, while yellowness and redness decreased. The dehydrated sprouted wheat exhibited excellent reconstitution andkeeping quality. The dehydrated sprouted wheat flour can be used for making noodles, pasta, laddu, bread, unleavened bread, porridge and gruels for newborns.

The hydrodynamics, kinetics as well as energy and exergy analyses of fluidized bed drying of rough rice under various experimental conditions were investigated. Drying experiments were conducted at drying air temperatures of 55, 60, and 70°C, superficial fluidization velocities of 2.3, 2.5, and 2.8 m/s, solid holdups of 0.66 and 1.32 kg, and rough rice initial moisture content of 0.25 d.b. Various popular drying models were used to fit the drying data. It was found that the fluidized bed hydrodynamics of the rough rice was uniform and stable. The drying rate was found to increase with increase in drying air temperature and superficial fluidization velocity, while decreased with increase in solid holdup. Statistical analyses showed that the Midilli et al. model was the best model in describing fluidized bed drying characteristics of the rough rice. The results showed that the values of energy efficiency were higher than the corresponding values of exergy efficiency during the entire drying process. Furthermore, at initial stage of drying, the energy and exergy efficiencies were higher than those at the end of drying. It was also found that both the energy and the exergy efficiencies increased with increasing drying air temperature and solid holdup, whereas decreased with the increase in superficial fluidization velocity.

Membrane bioreactor (MBR) provided with spiral wound modules of polyacrylonitrile ultrafiltration membranes was used to treat the wastewater obtained from primary and secondary processing operations of a poultry plant. The membrane bioreactor consisted of 3 tanks; an aerobic bioreactor, anoxic settling tank, and a third tank from which a permeate was drawn across ultrafiltration membranes for final discharge to a municipal sewer or for reuse in the processing of raw product. The Cleaning and backflush schedules were conducted to determine the best regimen for maximum permeate flux and for their effect on retention times in each of the biological treatment tanks. Continuous operation of MBR for 24 h period with no backflushing resulted in flux decay that led to a substantial change in retention times. The best operating cycle was found to be 1 h filtration followed by 120 s backflush or 20 min filtration followed by 20 s backflush. Significant reduction in particle size, COD and BOD (>90%) and reduction of microbial load by 4 – log levels in MBR effluent made it fit for reuse.

The purpose of this study was to develop a numerical model to predict the temperature distribution in cylindrically shaped cooked rice samples during microwave reheating and to give impetus to a uniform microwave-heating design. Cylindrically shaped instant rice was reheated by continuous microwave application, and the sample temperature was measured to determine the internal temperature profile which resulted in a desired uniformity of temperature observed using the non-uniformity temperature evaluation. A finite difference method was used to predict the temperature distribution of the cylindrical rice during microwave reheating and applying Lambert’s law to calculate the microwave power absorption in a large sample of cylindrically shaped instant rice. In order to solve the numerical model of heat transfer, the thermal and dielectric properties of instant rice were measured with respect to temperature. Our results showed that the temperature had a significant effect on the specific heat and dielectric loss of rice, while the thermal conductivity and dielectric constant were unaffected. The numerically predicted temperature distributions were in good agreement with the measured ones of instant rice.

Grape leaves ( Vitis vinifera L.) weighing 50 g (±0.08) with a moisture of 4.08 kg (moisture) kg −1 (dry matter) (75.35% wb) were dried using three different drying methods: microwave, air and combined microwave-air. Drying continued until the leaf moisture decreased to 0.14 (±0.01) kg (moisture) kg −1 (dry matter) (9.07% (±0.20) wb). Drying periods lasted 5–11, 30–70 and 1.5–6 min for microwave, air and combined microwave-air drying, respectively, depending on the drying level. In this study, measured values of moisture were compared with values of predicted obtained from several thin-layer equations; the Alibas Model was found to have the best fit. The optimum drying period, color and ascorbic acid content were obtained by using the combined microwave-air drying method with the optimum combination of 500 W of microwave power at a temperature of 75°C.

For the design of modified atmosphere packaging, it is necessary to know the influence of time and temperature on the respiration rate (RR) of fresh produce. RR of fresh fig and diced papaya was measured at three temperatures (10, 20 and 30°C) for storage time of 1–5 days under aerobic condition using closed system method. The aim was to determine the influences of storage temperature and time on RR of fresh fig and diced papaya. It develops and validates a combined predictive mathematical model based on the Arrhenius equation and Weibull distribution model. Temperature and time had a significant effect on RR. of fresh fig and diced papaya ranged from 16.2 to 45 and 25.5 to 114.9 ml kg –1 h –1 and ranged from 11.5 to 51.9 and 23.9 to 113 ml kg –1 h –1 , respectively, over the three storage temperatures tested. RR increased significantly four- to fivefolds with increase in temperature from 10 to 30°C. Temperature and the interaction of time and temperature had the significant effect on and . Arrhenius and Weibull distribution models successfully fitted the experimental data, adequately describing the influence of temperature and time on RR of fresh fig and diced papaya. This model can be used to predict RR at different temperature and time. The model which was tested at 15°C for its validity showed good agreement between experimental and predicted data. These models would help to choose the optimum packaging for selected fruits.

Separation of unshelled peanuts containing three or more kernels and then niche marketing them can potentially increase the value of unshelled peanuts and thus the profit of peanut producers or processors. Effective identification of peanut pods with three or more kernels is a critical step prior to separation. In this study, a machine vision system was teamed up with neural network technique to discriminate unshelled peanuts into two groups: one with three or more kernels and the other with two or less kernels. A set of physical features including the number of bumps, projected area, length and perimeter, etc., were extracted from the images taken and used to train an artificial neural network for discriminating the peanuts. It was found that among all the selected features, the length, the major axis length and perimeter have the best correlation with the number of kernels (correlation coefficient r = 0.87–0.88); the area and convex area have good correlation ( r = 0.85); the eccentricity, number of bumps, and the compactness have relatively lower correction ( r = 0.77–0.80); the solidity and the minor axis length have the least correlation to the number of kernels ( r = −0.415–0.26). The best discrimination accuracy obtained for peanut pods with three or more kernels was 92.5% for the conditions used in this study.

Gac fruit ( Momordica cochinchinensis Spreng) aril contains high levels of bioactive compounds including β-carotene, lycopene and fatty acids. Therefore, it is important to find an extraction method of Gac oil resulting in the highest content of bioactive compounds. The effects of microwave and air-drying pre-treatments of Gac aril prior to hydraulic pressing and Soxhlet extraction on the oil yield, nutrients and chemical properties of the oil were compared. Results showed that the highest oil yield could be obtained when the aril was microwave-dried before Soxhlet extraction. This finding was explained by microstructural changes of the dried arils. Microwave-drying prior to pressing resulted in the highest content of β-carotene (174 mg/100 mL) and lycopene (511 mg/100 mL) in the oil extract. Oleic acid (48%) and linoleic acid (18%) were found to be the dominant fatty acids in the oil extracts. Gac oil with the lowest acid (0.69 mg KOH/g) and peroxide values (1.80 meq O 2 /kg) was extracted when microwave-drying was applied prior to pressing. It can be concluded that the microwave drying pre-treatment before pressing was better than the air-drying pre-treatment for extracting Gac oil of high quality.

The effect of a pulsed electric field (PEF) on the microstructure of some amino acids was studied. Raman spectrum was used to determine the effect of PEF on tyrosine, tryptophan, proline residues, histidine, arginine, aliphatic amino acid, disulfide bond, and polypeptide backbone in soy protein isolates (SPI). Results suggested that increasing the intensity of PEF gradually to 50 kV cm−1 led to a reduction in gauche C–S conformation of CCSSCC dihedral angles. The increase of the PEF intensity caused an increase in the gauche–gauche–gauche conformation of the disulfide bond accompanying a decrease in α-helix and β-sheet and an increase in antiparallel β-sheet and disorder structure. A critical pulse intensity of 30 kV cm−1 was observed for unfolding and reassembling of SPI, which was verified in our previous study (Liu et al., Eur Food Res Technol 233:841–50). When the pulse intensity gradually increased to around 30 kV cm−1, the exposure of tyrosine and tryptophan, the vibration of CH2 wagging in proline and CH2 in the midazole ring of histidine, the vibration of C—H bending and C—N stretching inside a charged arginine, and asymmetric H—C—H bending deformation vibration in CH2 and CH3 groups in aromatic and aliphatic amino acids gradually increased, suggesting an unfolding of protein molecules. When the pulse intensity continually increased from 30 to 50 kV cm−1, the microstructure of all above amino acids decreased due to the reassembly of unfolding proteins.

A novel glycerol-plasticized and citric acid (CA)-modified starch/carboxymethyl cellulose (CMC)/montmorillonite (MMT) bionanocomposite films were prepared from corn starch by casting, to study the effect of the 10% CA, 10% CMC and four different loadings of MMT on the properties of starch films. Atomic force microscopy surface analysis showed that starch/CMC/MMT films had the highest roughness. X-ray diffraction test showed that the clay nanolayers formed an intercalated structure in the bionanocomposites. However, completely exfoliated structure formed only in the pure starch/MMT nanocomposites (without CA and CMC). CA, CMC and MMT improved mechanical properties of starch films. MMT had the greatest effect on the mechanical properties. The MMT addition at content of 7% caused to increase in ultimate tensile strength by more than threefold in comparison to modified starch/CMC films. The water vapor permeability (WVP) decreased significantly ( p < 0.05) by the addition of CA and CMC. When the MMT content of the starch films reached to 7%, the WVP decreased about 75% in comparison to the neat starch film. However, the hydrophilic character of bionanocomposites increased as the increasing of MMT content.

The aim of this research was to evaluate the stability of spray-dried soluble maté ( Ilex paraguariensis) and its total polyphenol content determined with the Folin–Ciocalteu assay, after it was elaborated with three different maltodextrin concentrations (0, 7.05 and 14.10% w/v) using experimental data of water activities and glass transition temperatures. Adsorption isotherms were determined for these three materials at 25°C between water activity values ( a w ) of 0.1 and 0.85 (resulting in values of water content between 0.04 and 0.33 g of water/g of dried solid). Glass transition temperatures varied from 15 to 52°C. At room temperature powder containing 14.10% of maltodextrin at a w =0.55 was below the glass transition temperature, while the two other compositions were below their T g and stable at a w =0.40. In the spray drying conditions analyzed, the loss of polyphenolic compounds is negligible. The total polyphenol content varied between 28 and 45 chlorogenic acid equivalents (g % dry powder).

The extrudates prepared under the optimized conditions of flour proportion (rice flour, pulse powder and carrot pomace), moisture content, screw speed and die temperature, were fried at temperatures of 170, 180, 190 and 200°C and for a time of 5, 10 and 15 s. Based on sensory characteristics, the selected product was stored for a period of 6 months in metalized polypropylene and evaluated for free fatty acid, peroxide value, hardness, crispiness, colour and beta carotene. The increase in colour L -values, b -values, oil absorption and decrease in colour a -values in carrot pomace–based rice extrudates was observed with the increase in frying temperature and time. The product obtained at 180°C for 15 s was rated better. The decrease in free fatty acid, colour L -values, b -values, crispiness and beta carotene and increase in peroxide value, hardness and colour a -values in carrot pomace–based rice extrudates was observed with the increase in storage period. However, the quantitative change in attributes suggested the acceptability of the product even after the storage of 6 month.

A study was conducted to determine the effects of moisture content and energy of impact on the cracking characteristics of walnuts. A sample of fresh harvested walnuts was divided into four portions and conditioned under sunshine for different time durations to obtain different levels of moisture content [9.2–29.7%, wet basis (w.b.)]. An impact test apparatus was used to apply different impact energies in the range of 0.13–1.11 J to samples with different moisture content. Data obtained on the quantity of fully cracked and unbroken kernel, fully cracked but broken kernel and uncracked nuts were used in the computation of the nuts cracking characteristics. Results showed that moisture content, impact energy and interaction effects of these two variables have significant effect on the walnuts cracking characteristics. Full cracking of nuts increased with impact energy and decreasing moisture content. The optimum moisture content for cracking walnuts that gave the best result combination of high whole kernel yield and low kernel breakage was found to be about 16%. The optimum impact energy for cracking was found to be about 1.01 J (1.01 ± 0.1 J). The results of this study show that development of a centrifugal impact cracker, which uses impact to crack walnuts, is possible. In the designing of the walnut cracker, the radius and speed of the cracker should be such that create impact energy and velocity of about 1.01 J and 11 m/s, respectively, and walnuts should be conditioned to the moisture content of about 16% for optimum efficiency.

Karkade calyces’ samples (variety Rahad) collected from different local sites were spray dried, and the powder samples were analyzed physically, chemically and microbiologically. The particle size of the various karkade powder samples ranged from 11.8 to 14.1 μm, while the flowability (angle of repose) ranged from 41° to 43° 20′. The reconstitution properties slightly varied when the various karkade samples were compared. The ranges of wettability, sinkability and dispersibility were 320–370 s, 800–850 s and 0.04–0.05 OD, respectively. The bulk density ranged from 0.57 to 0.65 g/ml, and the yield of karkade powder of the various samples ranged between 31.4 and 34.3%. The spray-dried samples from different sites were comparable in most of the chemical components, and they contained relatively good amount of macro- and micronutrients and high nutritive value. Virtually, all the spray-dried karkade powder samples were devoid of coliform, staphylococci and Salmonella cells.

Optimization of fluidized bed drying of sesame seeds was done by response surface methodology (RSM) and genetic algorithms (GA). Effect of drying parameters (drying temperature (40, 50, 60°C), drying time (60, 120, 180 min), air velocity (1, 1.5, 2 m/s) and bed depth of dryer (1–3 cm) was investigated based on the quality attributes of dried seeds. These factors were optimized with respect to the moisture ratio, color indices, and texture parameters (hardness and fracturability). The obtained models showed very well fitness with experimental data. The coefficients of resulting models with RSM were further optimized using GA. It was revealed that GA-optimized models have better fitness with the experimental results than RSM models. Our results suggest that sesame seed dried in 40–45°C for 115–120 min with 1 m/s air velocity had the lowest moisture content and color changes and the best texture.

The study investigated the use of impingement methods for cooling of fruits and vegetables. Raw materials were cooled in air at 0°C temperature flowing from nozzles of 0.02 m diameter with speed in the range of 10–51 ms −1 and for comparing, in the water at the same temperature. Raw mass change, value of heat transfer coefficient in the system and the cooling time were analyzed. The mass losses are dependent on air velocity at the nozzles exit, increase in the cooling air velocity permits a reduction in the losses. The mean value of heat transfer coefficient were found within the 12–44 W(m 2 K) −1 range. It was found that the impingement method can be used for rapid cooling of fruits and vegetables, characterizing the process parameters comparable to the cooling of water.

Tapioca contains very high starch content and therefore could be used to obtain a good quality puffed product. Tapioca powder added with roasted peanut to give nutty flavor and taste was used to develop ready-to-eat (RTE) snack utilizing high temperature short time (HTST) air puffing process with center composite rotatable design (CCRD). The effects of process parameters viz., puffing temperature (200–260 °C), puffing time (30–90 s), and raw material parameters viz., initial moisture content (30–40%) and roasted peanut proportion (10–20%) on quality attributes such as final moisture content, expansion ratio, color ( L value, a value), and crispness of the products were investigated and optimized using response surface methodology (RSM). The optimum quality attributes of the product in terms of final moisture content (4.7%db), expansion ratio (1.67), L value (70.96), a value (1.83), and crispness (12.1) were obtained with 20% added peanut, 35% initial moisture content, 245 °C puffing temperature and 60 s puffing time. The sensory evaluation of the optimally processed snack added with spices to enhance taste, showed the product to be crisp and highly acceptable.