Effect of gelatin and acacia gum on anthocyanin coacervated microcapsules using double emulsion and its characterization.

The present study was aimed to develop a stable microencapsulated anthocyanin from black rice bran using double emulsion complex coacervation technique. Nine microcapsule formulations were prepared using gelatin, acacia gum and anthocyanin at ratios of 1:1:0.5, 1:1:0.75 and 1:1:1 respectively. The concentration of gelatin and acacia gum used were 2.5, 5 and 7.5 % w/v. Subsequently, the coacervated microcapsules were obtained at different pH (3, 3.5 and 4), freeze-dried and evaluated for their physicochemical properties, morphology, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction pattern (XRD), thermal behaviour and stability of anthocyanin. The results obtained for encapsulation efficiency of anthocyanin with high values (72.70 to 83.65 %) indicated that the encapsulation process was effective. The morphology of the microcapsule powder was analysed and exhibited round, hard, agglomerated structures and relatively smooth surface. The thermal degradation behaviour of microcapsules displayed endothermic reaction confirming the thermostability of the microcapsules where the peak ranged from 83.7 to 97.6 °C. The stability studies in terms of retention of total anthocyanin content were observed at different storage conditions; both under refrigerated condition (7 °C) and at room temperature (37 °C). The results indicated that the microcapsules obtained through coacervation can be an alternative source to develop stable nutraceuticals.

Effect of ultrasound, centrifugation, and enzymatic pretreatments on phytochemical properties and membrane fouling during microfiltration of Sohiong (Prunus nepalensis L.) juice.

The study aimed to investigate the effects of various pretreatment methods on sohiong fruit juice during the microfiltration process. The ultrasound, centrifugation, and enzymatic pretreatment processes were used before the microfiltration process of the juice. The highest total phenolic content, anthocyanin content, and antioxidant activity of sohiong fruit juice were observed after enzymatic pretreatment. However, the browning index and color of the sohiong juice deteriorated with enzyme pretreatment. The fouling behavior of the microfiltration process for the pretreated sohiong juice was well explained by the complete pore-blocking model as the coefficient of determination (R 2 ) varied from 0.821 to 0.971. All pretreatment methods significantly (p ≤ 0.05) increased the initial flux of the microfiltration process, and the highest flux was observed for the enzyme pretreated juice. Furthermore, as compared to alternative pretreatments following microfiltration, the enzyme pretreated fruit juice had a high sensory acceptance. The work manifested a way to develop high-quality sohiong fruit juice with a low fouling tendency.

Effect of natural deep eutectic solvents on thermal stability, syneresis, and viscoelastic properties of high amylose starch.

This work aimed to use natural deep eutectic solvents to modify the thermal, textural, freeze-thaw, and rheological properties of high amylose rice starch. Three different natural deep eutectic solvents (NADES) composed of sugar and organic acids were applied to modify the properties of starch dispersion. In presence of NADES, the onset temperature of starch was decreased, in comparison with starch in aqueous and glycerol medium. During thermal decomposition, starch with the aqueous and glycerol systems showed two-step weight losses whereas with NADES starch showed single-stage weight losses or decomposition. Moreover, negligible syneresis was observed for starch-NADES dispersion after 3rd cycle of the freeze-thaw process. The flow behavior of starch-NADES dispersion follows Herschel-Bulkley models as R2 (0.996 ≤ R2 ≤ 0.999) are higher than the Mizrahi-Berk model. The flow behavior index (n) of starch-NADES dispersion was closer to 1, indicated a nearly Newtonian fluid. The loss modulus (G″) value of starch-NADES dispersions was markedly higher than the corresponding storage modulus (G') value and thus materials behaved like viscoelastic liquid. The present study manifested a green way to modify the properties of the high amylose starch to improve the processing stability.

Influence of extrusion cooking on phytochemical, physical and sorption isotherm properties of rice extrudate infused with microencapsulated anthocyanin.

The effect of extrusion cooking on the quality of rice extrudate with infused microencapsulated anthocyanin was investigated. The moisture sorption isotherm of the extrudate was also studied. The rotatable central composite design was used to optimize the extrusion process and the optimized conditions were: screw speed, 121 rpm; barrel temperature, 91.89 °C; and moisture content, 22.03%. The extrudate showed anthocyanin content of 0.218 mg/L; true density, 1.48 g/cc; water activity 0.51, water solubility index, 7.49%; and specific mechanical energy, 31.39 kJ/kg. The antioxidant activity and solubility of the extrudate were higher as compared with native extrudate. The moisture sorption isotherm of the extrudate was found to follow type III isotherm behavior according to the Brunauer-Emmett-Teller classification. The sorption isotherm was analyzed using several models and the Caurie and Peleg models were best fitted with the extrudate isotherm data. The present work manifested a way to develop antioxidant rich extrudate.

Physicochemical and phytochemical properties of foam mat dried passion fruit (Passiflora edulis Sims) powder and comparison with fruit pulp.

The aim of the present study was to develop purple passion fruit powder using the foam mat dried process. The possible effect of whipping time, methylcellulose concentration, and drying temperature on physicochemical and phytochemical properties of foam mat dried passion fruit was evaluated and compared with fruit pulp. The drying process was optimized using central composite design and optimum conditions were whipping time 2.78 min, methylcellulose 2.58%, temperature 44.05 °C. At the optimum condition vitamin C, total phenolic compound and hygroscopicity were 34.67 mg/100 g, 258.12 mg GAE/100 g, and 21.12%, respectively. The artificial neural network was applied to predict experimental outcomes. The phytochemical properties in terms of (±)-α tocopherol, D-α-tocotrienol, ß-carotene, and phenolic acid were determined using RP-HPLC. The foam mate dried powder contained a higher amount of ß-carotene (13.26 mg/100 g), total phenolic compound (258.12 mg/100 g) and phenolic acids than fruit pulp whereas fruit pulp was contented higher amount of (±)-α tocopherol (171.1 mg/100 g) and D-α-tocotrienol (27.19 mg/100 g). The study manifested foam mate drying as an effective way to develop passion fruit powder.

Effect of ionic liquid on sol-gel phase transition, kinetics and rheological properties of high amylose starch.

The effect of 1-butyl-3-methylimidazolium chloride (BMIMCl) as a plasticizer on sol-gel phase transition, rheological, and physical properties of high amylose rice starch was studied. The inter-relationships of parameters were determined using principal component analysis. The sol-gel phase transition temperature and storage modulus of starch was varied significantly (p ≤ 0.05) in the presence of BMIMCl. The sol-gel phase transition temperature of native starch was varied between 53.99 and 39.7 °C, whereas, for starch with ionic liquid varied between 49.50 and 40.6 °C. The changes in storage modulus (G') during the sol-gel phase transition were suitable with first order kinetics. The temperature dependent rheology of starch during the sol-gel phase transition was efficiently (0.93 ≤ R2 ≤ 0.98) explained using the Arrhenius model. The thermal stability of the gel was improved in the presence of BMIMCl. The textural and electrical properties of the gel were significantly affected by the presence of BMIMCl. The inter-relationships between the parameters were developed and the initial temperature, resistance, and storage modulus showed a strong interrelation.

Microencapsulation of anthocyanin extract from purple rice bran using modified rice starch and its effect on rice dough rheology.

The investigation aims to microencapsulate anthocyanin extract from purple rice bran with modified glutinous rice starch to provide stable anthocyanin powder. The modified glutinous rice starch was used as wall material where anthocyanin extract was a core material for microencapsulation. The microencapsulation was carried out in a spray dryer, and the process was optimized using a rotatable central composite design. The effect of independent parameters, viz., starch concentration, inlet air temperature, and atomizer pressure, on the dependent parameters, such as encapsulation efficiency, anthocyanin content, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, true density and water activity were investigated. The optimum values of the spray drying process parameters were 6.01% of starch concentration, 168.78 °C inlet air temperature and 4.96 MPa atomizer pressure. The physical characteristics of spray-dried powders were investigated in term of water activity (0.51), solubility (51.83%), bulk density (1.404 g/cm3), porosity (0.20), and diameter (6.44 µm) and the Hausner ratio (1.020). The thermal, crystallinity and surface morphology of the microencapsulated particles were also comprehensively studied using DSC, XRD, FTIR, and SEM. The storage stability of microencapsulated anthocyanin showed more stability at 4 °C than at 25 °C for 90 days. The microencapsulated particles also have an effect on the steady-shear rheology of the rice dough.

Effect of extrusion conditions on the physicochemical and phytochemical properties of red rice and passion fruit powder based extrudates.

The passion fruit powder blended rice flour based extrudate was developed and investigated in terms of physicochemical and phytochemical properties. The extrusion process was performed using a twin screw extruder and optimized using rotatable central composite design followed by response surface methodology. The effect of process parameters such as temperature (80-150 °C), screw speed (200-400 rpm), moisture content (20-30%) and passion fruit powder (0-15%) on product quality was investigated. The optimum extrusion conditions of temperature, screw speed, feed moisture content, and passion fruit powder were 97.50 °C, 250 rpm, 25.20% and 11.25%, respectively. At optimum condition, the predicted values of responses were expansion ratio 8.05, water absorption index 2.77, total phenolic content 129.492 mg GAE/100 g and DPPH scavenging activity 65.79%. A comparison between optimized and control extrudates revealed that thermal, crystallinity and morphological properties of extrudates differed significantly. The comparison was also conducted in terms of FT-IR, SEM-EDS and HPLC analysis. The phytochemical properties showed that ß-carotene, cyanidin-3-glucoside, peonidin-3-D-glucoside chloride were higher in control whereas the optimized sample evinced more (±)-α-tocopherol and D-α-tocopherol.

Effect of alcohol-acid modification on physicochemical, rheological and morphological properties of glutinous rice starch.

In the present study chemical modification of glutinous rice starch was carried out using 1-Buatnol-hydrochloric acid with varying time and temperature. The changes in physico-chemical, dynamic rheological and morphological properties of starch during hydrolysis was investigated. There was a significant increase in water solubility of starch due to modification; however, swelling and sedimentation value decrease after modification. The peak, hold and final viscosity of modified starches were decreased significantly as compared to native starch. Thermal properties and dynamic rheological properties of rice starch were changed with the change in time and temperature during modification. The storage (G') modulus, loss (G″) modulus, dynamic viscosity (η') and complex viscosity (η*) of modified starches were varied significantly. Analysis of microstructure revealed that the hydrolysis altered morphology of starch granules. The hydrolysis was affected the surface properties and granule size of rice starch. These results suggested that 1-butanol-HCl hydrolysis of glutinous rice starch can be a preferred way of modification.

Acrylamide in snack foods.

Research on acrylamide has been going on for the last four decades. However, its presence in carbohydrate-rich and high temperature processed foods was confirmed in 2002, after which a significant progress in this field has been made. A number of studies were conducted to explore the mechanism of its formation in carbohydrate-rich foods. Carbohydrate, protein, and fat are the main constituents of food, which are mainly responsible for the formation of acrylamide, and thus, a number of investigations were carried out to reduce its quantity in food. Moreover, various studies regarding carcinogenic and neurotoxic effects of acrylamide on animal models suggested that acrylamide can produce tumor in the thyroid gland, testes, mammary gland, lungs, clitoral gland, brain, and also enhance mutation, a step to cancer. Therefore, this review addresses the studies conducted since recently on the toxicological effects, formation mechanism and reduction of the formation of acrylamide in snack foods.