Band 11, Heft 4 -

Optimization of cleaning-in-place (CIP) procedures using bench-scale equipment is severely restricted by the short testing times (typically 1–3 days) compared with the normal lifespans of industrial membrane materials (years). In our research, industrially used polyethersulfone membrane material (“aged membrane”) was migrated to a lab-scale filtration apparatus. Performance (flux) of aged membranes was found to be 10% lower compared to new membranes of the same specification. For each set of membranes, performance was on the same level during multiple filtrations with intermediate CIPs. Reducing the CIP from a three-step procedure (caustic, enzymatic, acid) to only one step (caustic) had no influence on subsequent filtration performance even though flux recovery after reduced CIP was as low as 38% compared to 90% after three-step CIP. Consequences of reduced cleaning could first be observed in the subsequent CIP where the level of resistance during the respective CIP steps was increased.

To study the effects of indenter surface shapes on the crushing of foods, a double-tooth indenter (DTI), a single-tooth indenter (STI), a cylinder-type indenter (CTI) and a wave-type indenter (WTI) were developed by simulating the crown of human molar. Crushing experiments and analysis of finite element simulation were done. Crushing effect was determined by the wet sieving and weighing method; numerial simulations were performed for the crush process using the non-linear contact finite element method. The results showed that the DTI yielded the smallest median size among the four indenters, and the granulometric characteristics of food bolus are similar to human boluses, have higher von Mises stress value than others, higher crush efficiency, bigger crush stress, more stress concentration area than others. The crushing efficiencies of STI and CTI are very close. This study can improve the indenter parameters of texture analyzers and optimize the design process of a food chewing robot.

Trans -free interesterified fat was prepared from binary blends of rice bran stearin (RBS) and fully hydrogenated soybean oil (FHSBO) with RBS/FHSBO mass ratio of 50:50, 60:40 and 70:30. Commercial lipozyme RM IM (10 wt% of total substrate) was used to catalyze the reaction. Coconut oil (CO, 20 wt% of RBS/FHSBO) was also added to increase the medium-chain fatty acids content. The enzymatic interesterified fats EIEF were evaluated for their physical properties (i.e., solid fat content (SFC), polymorphism and crystal morphology) and the bioactive phytochemical contents. The SFC curves after interesterification were flattened, indicating a wide plastic range. SFC of the EIEF with different ratio (RBS/FHSBO=50:50, 60:40 and 70:30) at 25 °C were 34.2, 25.7 and 17.8%, respectively, while the physical blends at the same ratio showed 41.4, 35.7 and 27.7%. From X-ray diffraction (XRD), β polymorphic form was observed in physical blends, whereas only β’ crystal form was discovered in EIEF, which is most desired for shortenings and margarines preparation. EIEF contained 416.7–602.4 mg/100 g oryzanol, 25.4–36.5 mg/100 g total tocopherols and 319.3–431.8 mg/100 g total phytosterols, which could confer health benefits. The results indicated that EIEF may have a potential use in shortenings and margarines preparation.

The study aimed to optimise the ultrasound-assisted aqueous extraction of oil, β-carotene and lycopene from powdered microwave-dried gac arils. Ultrasound power, extraction time, powder particle size and the ratio of water to gac powder during the extraction, the centrifugal force used to recover the extracted components were investigated. Microwave-drying followed by aqueous extraction without ultrasound-assistance and air-drying followed by aqueous extraction with or without ultrasound-assistance was also carried out for comparisons. The gac material left behind after the extractions was also investigated using scanning electron microscopy (SEM). The results showed that ultrasound power of 32 W/g of aril powder, extraction time of 20 min, powder particle sizes of 0.3–0.5 mm, a ratio of water to powder of 9 g/g and a centrifugal force of 6,750× g gave optimal extraction efficiencies for oil (90%), β-carotene (84%) and lycopene (83%), and the oil had a low peroxide value (PV) of 2.2 meq/kg. The SEM analysis confirmed that the combination of microwave-drying followed by ultrasound-assisted aqueous extraction caused strong disruption of the gac aril cellular structures, which was consistent with the high extraction of oil, β-carotene and lycopene obtained with the combination. It was concluded that gac oil containing high amounts of β-carotene and lycopene and having a low PV could be extracted using microwave-drying and ultrasound-assisted aqueous extraction.

In this study, cow (W)’s milk was replaced by soy (S), coconut (C) and various combinations of coconut or cow milks with soy milk in order to produce fermented probiotic ice cream. The changes in ice cream eating qualities and physical properties were evaluated. Fermented ice cream containing vegetable milks showed a slower melting rate and higher apparent viscosity and particle size and also lower total acceptability than fermented cow milk ice cream (control). Ice creams containing Lactobacillus acidophilus (La-05; L) showed a lower melting rate and higher apparent viscosity and particle size than ice creams containing Bifidobacterium bifidum (Bb-12; B). Regardless of the starter culture used, all of sensory analysis scores decreased in ice creams with higher soy milk amount. The vegetable milks may offer ice cream manufacturers an alternative source of cow milk as a functional ice cream.

The treatment of a food in liquid media involves mass transfer and could aid to preserve some food properties. The assistance of ultrasound (US) could even improve the process. Therefore, the aim of this study was to evaluate US (frequency 25 kHz, powder intensity 8 kW m –3 ) in tomato treatment in sucrose and NaCl solutions, common osmotic agents. Moreover, for testing the influence of the media, distilled water and maltodextrin solution completed the set of tested liquids. Water loss (WL), solid gain (SG), water activity ( a w ), color parameters, like the total color difference (Δ E ) and microstructure were evaluated. The advantages of NaCl and sucrose solutions were the high WL and SG values besides low a w and Δ E . The alterations in the microstructure of US-treated samples in distilled water or maltodextrin suggested that a product with low solid incorporation and reduced drying time could be obtained in a further drying.

The present study was aimed to investigate the potential of Penicillium notatum for the production of pectin lyase under solid state culture using wheat bran as substrate. Different process parameters were optimized using completely randomized design for enhanced production of the pectin lyase. P. notatum showed maximum production (1875 U/gds) of pectin lyase with substrate amount 15 g/250 ml, moisture level 60%, pH 6, incubation period 120 h at 30°C. Pectin lyase activity was further improved with the addition of maltose and ammonium sulphate as carbon and nitrogen additives (1%), respectively. Partial purification of enzyme was carried out by ammonium sulphate precipitation at 80% saturation level. The P. notatum pectin lyase showed maximal activity at 65°C and pH 8. K m and V max values were 0.29% and 0.487 µmol/min, respectively. Energy of activation was found to be 5.33 kJ/mol. A detailed kinetic study of thermal inactivation was carried out. The results showed that pectin lyase exhibited resistance against thermal unfolding. Effect of various metals on pectin lyase activity was also investigated. All the metals showed inhibitory effect on the enzyme activity. The present investigation revealed that pectin lyase isolated from P. notatum is thermally stable and alkaline in nature.

In this study, the effects of different current and wave forms of electrical application by electroplasmolyzator on the production of tomato juice were investigated. The whole electrical design can be divided into three subtitles. The three subtitles are used for only auto-transformer outputs for “AC (alternative current) voltage”, and the AC rectification for “DC” (direct current) voltage and the gate drive of the switching devices for “square waves”. Yield, lycopene content and color values were compared for these different current and wave forms. As a result the yield increase was found mostly in the AC-treated group which has square wave form and bipolar single phase (100 V–90 s). Lycopene was also found mostly in the same group. Significant differences were found between the groups that are treated with different current and wave forms.

The influence of osmotic pretreatment on nectarines with solutions of glucose syrup and sorbitol and subsequent dehydration at different temperatures (60 °C, 70 °C, or 80 °C) was evaluated. The kinetics of moisture loss during drying was obtained and mathematical models were adjusted to estimate the kinetic parameters. Effective diffusion coefficients were calculated using Fick’s second law. All drying kinetics exhibited only a falling-rate period during hot-air drying owing to moisture loss in the osmotic pretreatment. Moisture loss was favoured by the use of sorbitol, whereas the diffusivity of water increased when glucose was used as an osmotic agent. Logarithmic and Midilli et al. models best described the changes in moisture over time, whereas Fick’s second law estimated water diffusion coefficient values between 4.96×10 −9 and 2.43×10 −8 m 2 s −1 . These models may be employed to predict the optimum conditions for osmo-dehydrating nectarines under hot-air drying at the industrial level.

Iranian paddy (Fajr) is the most popular rice for export and consumption in Iran but it has poor milling yield. To solve this problem, parboiling has been used for improving its milling quality. In this study, the effect of various parboiling conditions (soaking at temperatures of 55–75°C and steaming times for 2–10 min) on some quality properties of Fajr paddy was investigated. After parboiling, the physical properties (degree of milling, head rice yield, lightness and color value) and mechanical properties (rupture force) of parboiled rice were measured. Head rice yield and mean value of rupture force increased significantly ( p < 0.05) from 50.10% to 62.11–67.05% and from 108.6 to 128.93–227.30 N, respectively. Also, the color value of parboiled rice increased significantly ( p < 0.05) by increasing the length of steaming time. The milling degree of unparboiled rice (17.03%) was significantly ( p < 0.05) higher than that of the parboiled rice (15.1–16.9% range). Soaking at 65°C and 4 min steaming time gave the highest values of head rice yield, lightness and rupture force. So, this treatment was found to provide the most desirable quality of Fajr parboiled rice.

In the present study the possibility of reduced-calorie sponge cake production with maltitol and oligofructose was investigated (control: 100% sucrose; M 1 : 100% maltitol; M 2 : 77% maltitol–23% oligofructose; M 3 : 23% maltitol–57% sucrose–20% oligofructose; M 4 : 25% maltitol–75% sucrose). The sensory and physical properties of the final product such as volume, specific volume, moisture and water activity, crust color, firmness and overall acceptability were evaluated. Among four samples, M 3 (maltitol–sucrose–oligofructose) showed very close results to the control in terms of water activity, firmness and sensory properties and even outmatched it in volume and specific volume. M 3 also presented darker crust in comparison with control. According to the results, M 2 and M 4 were also appropriate in some properties like volume, specific volume, water activity and crust color. M 1 showed the weakest physical and sensory attributes. Moisture was not affected by maltitol and oligofructose ( p > 0.05).

Brown rice was exposed to 60 Co source at 0, 2, 4, 6, 8 or 10 kGy doses and the effect of gamma irradiation treatment on physicochemical properties were investigated. L * value of brown rice was decreased with increase of irradiation dose, whereas a * and b * values increased. The results showed the decrease of kernel hardness, amylose content and pasting properties considerably with irradiation treatment. A-type diffraction pattern was observed in non-irradiated and irradiated rice samples and crystallinity was decreased with irradiation dose. Raman spectrometry showed the decrease of Raman band intensity at higher irradiation doses. Thermal properties of rice samples were decreased slightly after irradiation treatment. Pearson’s correlation studies revealed that irradiation dose was positively correlated with b * value and negatively correlated with amylose content and pasting properties.

This study investigated the moisture sorption isotherm (MSI) profiles of freeze-dried (FD) and boiled-dried (BD) abalone at 15°C, 25°C, and 35°C, and compared the quality characteristics of the abalone after rehydration. The equilibrium moisture content (EMC) and the calculated monolayer moisture content of FD abalone were higher than those of BD abalone. After rehydration, FD abalone showed a higher yield and a lower shear force than BD abalone. Additionally, the appearance of FD abalone was similar to that of fresh abalone, reflecting a potential application of FD to produce value-added dried abalone.

Foods (natural or processed) containing known biologically active compounds, which supplies clinically established and well-documented health benefits, are termed as functional food. Study objectives were to boost food functionality of spirulina, to optimize the required radiation dose, and to test functionality of spirulina both in vitro and in vivo . For this purpose fat binding capacity, sugar binding capacity, hydration property, antioxidative property, total polyphenol content were assessed at different radiation doses. A total of 30 rats were divided into three groups to carry out in vivo experiments to validate the outcomes of in vitro experiments. Targeted physico-chemical properties of spirulina were increased at their maximum level at 15 kGy radiation dose. In vivo experiments validated the outcomes of in vitro experiments. Though gamma radiation improves food functionality of spirulina at various radiation doses, but the optimum dose is recommended as 15 kGy.