Band 12, Heft 5 -

The effect of Tarragon essence concentration (0–1,000 ppm), whey protein concentration (0.7–2.8 % milk), calcium chloride (0.15–0.35 g/kg), rennet concentration (0.01–0.03 g/kg), starter content (0.01–0.03 g/kg), and renneting temperature (25–45 °C) on kinetic parameters of milk coagulation was investigated using statistical approach. A central composite design was used to investigate the effect of studied factors on coagulation parameters such as coagulation rate, lag time and inflection time. In general, with a decrease in whey protein concentration or an increase in starter level, rennet content and renneting temperature, coagulation rate increased while the lag time and time at inflection point decreased. Essence addition and calcium chloride did not have significant effects on rennet coagulation kinetic. The optimum conditions of milk coagulation were: rennet content, 0.025 g/kg of milk; whey protein concentration, 0.93 %; and renneting temperature, 44.9 °C.

In this research, thermosensitive liposomes (t-L) containing juglone were prepared with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and cholesterol by aether injection method. Morphological characteristics, encapsulation efficiency (EE), particle size, zeta potential, in vitro release, and cell viability of t-L were investigated and compared with those of conventional liposomes (c-L). Results indicated that t-L are multilamellar vesicles with lower negative charge, larger particle diameter, and higher EE than c-L. Moreover, in vitro juglone release from t-L was temperature dependent. Up to 60 % of the loaded juglone was released from t-L in 20 min when environmental temperature was increased from 37 °C to 42 °C; by contrast, >60 % of the drug remained inside for 24 h at 37 °C. Furthermore, MTT assay results revealed that t-L significantly increased the inhibitory effect on HepG2 cell growth and proliferation when these cells were exposed to hyperthermia; therefore, t-L could be applied for targeted therapy.

A comparison of chestnut polysaccharide extraction using ultrasound-assisted extraction (UAE) and hot water extraction (HWE) demonstrated that UAE is superior to HWE due to its higher extraction efficiency. Scanning electron microscopy (SEM), thermogravimetric analysis-differential scanning calorimetry (TGA-DSC) and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the ultrasound-assisted-extracted polysaccharide (UAEP) and hot water-extracted polysaccharide (HWEP). SEM images revealed that the UAEP and chestnut residue were crushed, with particle sizes that were smaller than those of the HWEP, which was related to the breakage of long-chain polysaccharides. TGA-DSC showed a higher transition temperature and enthalpy value for the UAEP than the HWEP, and the FTIR spectrum revealed typical characteristics of polysaccharides, with some differences between the UAEP and HWEP. The evaluation of antioxidant activities showed that the UAEP had stronger antioxidant capacities than the HWEP, regardless of the reducing power and DPPH-, ABTS- and hydroxyl radical-scavenging activities, suggesting that ultrasound is an optimal method to rapidly extract chestnut polysaccharide, a potential natural antioxidant.

The agave fructans as carrier agent can be an alternative to increase quality properties of blackberry. The aim of this study was to evaluate the effect of agave fructans concentration and inlet air temperature on quality properties of blackberry powder. Agave fructans concentrations were 50, 75 and 100 % (in base the total soluble solids percentage of blackberry extract), and the inlet air temperatures were 70–110 °C. A pilot-scale spray dryer was employed. Drying yield ranged from 58 to 94 % dry base. Encapsulation efficiency values varied between 48 and 100 % of anthocyanin concentration. The lower agave fructans concentration showed the best quality characteristics as lower water activity of 0.28, high anthocyanin retention of 98 %, high bulk density of 0.80 g/ml and the higher agave fructans concentrations showed the best stability properties as lower hygroscopicity of 0.013 g H20 /g solids and low particle temperature of 38 °C. The agave fructans improves good physicochemical and stability characteristics in blackberry powders.

In this assay, rabbit anti-β-conglycinin polyclonal antibody (Pab) was used as primary antibody and goat anti-rabbit IgG-horseradish peroxidase (HRP) was used as secondary antibody. The optimum incubating time of blocking, HRP and TMB (3, 3’5, 5’-tetramethylbenzidine) detected by the response surface and orthogonal test was 58, 140, and 20 min, respectively. The practical working range for the determination of β-conglycinin was 20–320 ng ml −1 . The recoveries of β-conglycinin in spiked soybean samples were between 95.8 % and 101.2 % with the relative standard deviation less than 6.9 % (intra-assay) and 8.2 % (inter-assay). The current method was used to analyze 80 different soybean obtained from different region of Jilin province and the detected results using the direct ELISA. Compared with the competitive ELISA, The results showed contents had no difference between two methods. The dcELISA assay provides a specific and sensitive method for detecting of soybean β-conglycinin in actual production.

Dynamic vapor sorption equipment (AQUADVS) was used to determine adsorption and desorption isotherms for powder rich in fiber (PRF) produced from Palm Date flesh of Sifri cultivar ( Phoenix dactylifera L.) at temperatures 25, 35 and 45 °C in a wide range of water activity (0.09–0.87). Equilibrium was achieved within 29 and 25 h for the adsorption and desorption process respectively. The obtained data were fitted to ten models (Peleg, GAB, BET, Halsey, Oswin, Smith, Modified Henderson, Adam and Shove, Modified Oswin and Modified Halsey). The results indicated that the PRF followed type III behavior. The empirical Peleg model was found to be the best to represent the experimental data in the water activity range 0.09–0.87. The isosteric heat of sorption and the differential entropy decreased by increasing the moisture content and can be predicted by polynomial functions. Glass transition temperatures ( T g ) of PRF were determined. The T g decreased as the moisture content increased and can be correlated using the Gordon and Taylor model ( R 2 =0.976). The PRF should be stored at moisture less than 9 d.b.% and temperature less than 35 °C.

This study seeks to investigate the effects of temperature (50, 60, 70 and 80 °C) and material thickness (3, 5 and 7 mm), on the drying characteristics of pumpkin ( Cucurbita moschata ). Experimental data were used to estimate the effective moisture diffusivities and activation energy of pumpkin by using solutions of Fick’s second law of diffusion or its simplified form. The calculated value of moisture diffusivity with and without shrinkage effect varied from a minimum of 1.942 × 10 –8  m 2 /s to a maximum of 9.196 × 10 –8  m 2 /s, while that of activation energy varied from 5.02158 to 32.14542 kJ/mol with temperature ranging from 50 to 80 °C and slice thickness of 3 to 7 mm at constant air velocity of 1.16 m/s, respectively. The results indicated that with increasing temperature, and reduction of slice thickness, the drying time was reduced by more than 30 %. The effective moisture diffusivity increased with an increase in drying temperature with or without shrinkage effect. An increase in the activation energy was observed due to an increase in the slice thickness of the pumpkin samples.

This study focusses on evaluating the effects of reciprocating agitation thermal processing (RA-TP) on the quality of canned potato cubes and whole radish packed in brine solution (1 % NaCl+1 % CaCl 2 solution). Experimental cans were subjected to RA-TP in a lab-scale steam retort at different temperatures (110–130 °C) and reciprocation frequencies (0–3 Hz). Color, texture, antioxidant activity and solids leached into the liquid were evaluated to characterize the quality of processed product. RA-TP resulted in superior quality retention in processed vegetables as compared to static retort (0 Hz) due to the associated shorter (up to 70 %) process times. In general, higher operating temperatures and reciprocation frequencies resulted in better retention of color and antioxidant activity. However, RA-TP also increased texture damage and nutrients/solids leaching, but these negative effects were milder at higher process temperatures. Therefore, high-temperature and high agitation frequency RA-TP concept with shorter process time could be effectively used for better quality retention. The optimal product quality was obtained at 130 °C retort temperature and 3.0 Hz reciprocation frequency for whole radish and at 130 °C retort temperature and 1.5 Hz reciprocation frequency for potato cubes.

In the present study, the effect of heat treatment on the activity of bacteriocin from Lactobacillus plantarum ATM11 was studied. The kinetic and thermodynamic parameters were calculated for the thermal inactivation of the bacteriocin over a time–temperature combinations in the range of 30, 45, 60 and 90 min and 60, 65, 70, 75 and 80 °C. Understanding the thermal inactivation of biopreservatives in a food matrix is essential to allow their proper utilization in food industry, enabling the reduction of heating times and optimization of heating temperature. The results indicate the different thermal stabilities with k -values between 0.0159 and 0.0225 min −1 . D -values decreased with increase in temperature, indicating faster inactivation of the bacteriocin at higher temperatures. These results suggest that bacteriocin is relatively heat stable with a z -value of 22.85 °C.

Response surface methodology was used to determine the optimum storage conditions of malta fruits that give minimum weight loss and maximum total soluble solid (TSS) retained value. Scavenger (3–5 g), polythene thickness (75–125 gauge) and fungicide concentration (75–200 ppm) were the factors investigated. Experiments were designed according to Box–Behnken design with these three factors, including central points. For each response, a second-order polynomial model was developed using multiple linear regression analysis. Applying desirability function method, optimum storage conditions were found to be 5 g scavenger, 125 gauge polythene thickness and 200 ppm fungicide concentration.