Journal of Food Science and Technology-mysore最新文献

In this study, ultrasound-assisted extraction (UAE) of natural pigment extraction from waste red beet stalks were optimized under four factors (extraction temperature, ultrasonic power, extraction time and solid-liquid ratio) by using three level Box-Behnken response surface design. Extraction temperature, ultrasonic power and solid-liquid ratio were significantly influenced the extraction yield of pigments. Extraction temperature of 53 °C, ultrasonic power of 89 w, extraction time of 35 min and SL ratio of 1:19 g/ml was identified as the optimal condition. Under this condition, the actual yield of (betacyanin of 1.28 ± 0.02 and betaxanthin of 5.31 ± 0.09 mg/g) pigments was well correlated with predicted values (betacyanin was 1.29 mg/g and betaxanthin was 5.32 mg/g).

The interest for producing wheat flour with health promoting effect and improved functionality has led to investigate new milling techniques that can provide finer flours. In this study, jet milling treatment was used to understand the effect of ultrafine size reduction onto microstructure and physicochemical properties of wheat flour. Three different conditions of jet milling, regarding air pressure (4 or 8 bars) feed rate and recirculation, were applied to obtain wheat flours with different particle size (control, F1, F2 and F3 with d50 127.45, 62.30, 22.94 and 11.4 μm, respectively). Large aggregates were gradually reduced in size, depending on the intensity of the process, and starch granules were separated from the protein matrix. Damaged starch increased while moisture content decreased because of milling intensity. Notable changes were observed in starch hydrolysis kinetics, which shifted to higher values with milling. Viscosity of all micronized samples was reduced and gelatinization temperatures (To, Tp, Tc) for F2 and F3 flours increased. Controlling jet milling conditions allow obtaining flours with different functionality, with greater changes at higher treatment severity that induces large particle reduction.

The effects of temperature, time, pressure and brine concentration were assessed during osmotic dehydration (OD) of H. edentatus fillet. The response surface methodology (RSM) showed that using vacuum during the OD process did not cause a statistically significant change (p > 0.05) on the water loss (WL), solid gain (SG) and water activity (aw). The other factors showed a statistically significant effect (p ≤ 0.05) on at least one of these responses. Through RSM, the following condition could be defined for the OD process: brine concentration at 25 % NaCl, 25 °C, 120 min and atmospheric pressure. The Azuara model was shown to be effective in predicting the WL and SG kinetics during the OD process. The simplified solution of Fick's second law of diffusion for a slab geometry was used to calculate the average values of apparent diffusion coefficient (Deff), namely 4.73 × 10(-10) m(2)/s for WL and 1.33 × 10(-9) m(2)/s for SG.

The storage stability of preservative-free peanut butter was evaluated for changes in physicochemical quality including moisture content and water activity, microbiological properties, oxidative stability and textural quality in terms of spreadability and firmness. The study was conducted for 16 weeks at storage temperature of 10, 25 and 35 °C on natural and pure peanut butter produced from two varieties of peanuts, the Virginia and Spanish TMV-2 varieties of China and India origin, respectively. The peanuts were ground using a high speed grinder for 2.5 and 3.0 min to produce peanut butter without addition of other ingredient. The natural peanut butter exhibited stability and had acceptable microbial count during storage. Storage at 10 °C gave similar textural quality with commercial product until week 8 and without appreciable loss in oxidative stability until week 12. At higher storage temperatures of 25 and 35 °C, oxidative stability was shortened to 4 weeks of storage. Among the factors of storage temperature and time, grinding time and peanut variety, storage temperature had the most significant effects on quality changes of natural peanut butter.

A microreactor for the chemiluminescence detection of copper (II) in water samples, based on the measurement of light emitted from the copper (II) catalysed oxidation of 1,10-phenanthroline by hydrogen peroxide in basic aqueous solution, is presented. Polymethyl methacrylate (PMMA) was chose as material for fabricating the microreactor with mill and hot bonding method. Optimized reagents conditions were found to be 6.3 × 10(-5)mol/L 1,10-phenanthroline, 1.5 × 10(-3)mol/L hydrogen peroxide, 7.0 × 10(-2)mol/L sodium hydroxide and 2.4 × 10(-5)mol/L Hexadecyl trimethyl ammonium Bromide (CTMAB). In the continuous flow injection mode the system can perform fully automated detection with a reagent consumption of only 3.5 μL each time. The linear range of the Cu (II) ions concentration was 1.5 × 10(-8) mol/L to 1.0 × 10(-4) mol/L, and the detection limit was 9.4 × 10(-9)mol/L with the S/N ratio of 4. The relative standard deviation was 3.0 % for 2.0 × 10(-6) mol/L Cu (II) ions (n = 10). The most obvious features of the detection method are simplicity, rapidity and easy fabrication of the microreactor.

There is a tendency towards the use of natural antioxidative substances due to toxic effects of synthetic antioxidants. The purpose of this research was to evaluate the effects of tocopherol and extracts from rosemary and ferulago on oxidation in a mixture (1:1, w/w) of sunflower seed oil and palm olein, during deep frying of potato slices. Besides the control groups, tertiary butylhydroquinone (TBHQ) served as a standard for comparison. The DPPH radical scavenging activities of extracts followed the order of rosemary10% > rosemary1% > rosemary0.1 % > ferulago 10 % > ferulago 1 % > ferulago 0.1 %. Frying performance of antioxidants were tested with regards to primary (peroxide value (PV)) and secondary (anisidine value (AnV), free fatty acids (FFA), total polar compounds (TPC) and volatile oxidation compounds such as hexanal and heptanal) oxidation products and by sensory evaluation. After frying process, rosemary extract treatment exhibited PV (1.2 meq O2/kg), FFA content (0.124 %), TPC (12.2 %), hexanal concentration (62.4 ng/g) and heptanal concentration (73.8 ng/g), which were significantly equal or sometimes less than those of TBHQ treatment ((1.23 meq O2/kg), (0.123 %), (12.6 %), (64.4 ng/g) and (74.1 ng/g), respectively). Whilst the ferulago extract showed higher PV (2 meq O2/kg) than the control sample, it was efficient in delaying secondary oxidative changes. Tocopherol markedly retarded primary stage but its activity fell down toward secondary oxidation products. The overall results of this research suggest that rosemary extract may be a good natural alternative to TBHQ, but further studies are necessary to investigate the use of ferulago extract.

Utilization of Indian sweetened yogurt (colloquially termed as Mishti Dohi), as vehicle for ACE inhibition and antioxidant activity, by added tryptic whey protein hydrolysate (TWPH) (@ 1, 2, 3 % v/milk), was attempted. Yogurt with 3 % TWPH exhibited non-significant (p > 0.05) difference for sensory attributes; but for body & texture; and maximum biofunctional properties, electing it for storage study (5 ± 1 °C). Flavor and body & texture scores registered significant (p < 0.05) decline under 14 days storage. ACE inhibition and antioxidant activity of control increased by 47.95 and 13.18 % and of experimental 24.58 and 13.43 %, correspondingly. Acidity rose to 1.18 % LA. Control samples conveyed 18.07 % and experimental of 20.77 % escalation for wheying-off. Tyrosine value was 27.04 μg.mL(-1). Among rheological attributes, firmness, quantified by texture analyzer TA-XT2i, dropped (p < 0.05), due to decrease of gel rigidity whereas work of adhesion revealed non-significant difference (p > 0.05), throughout.

A great deal of attention has been focused on the various health benefits apparently associated with consumption of fish oil. The incorporation of fish oils in food products is becoming increasingly widespread and a large variety of products is being marketed. However, the use of fish oil as functional nutritional ingredients in foods has been limited by its oxidative susceptibility. In the present study, attempts were made to develop fish oil fortified cookies as healthy snack foods by incorporating fish oil microencapsulate. Microencapsulation of fish oil was done by spray drying. Commercially available milk was used to form micro sized complexes with fish oil. Fish gelatin/maltodextrin were used as a wall material for encapsulation. Fish oil was added in three forms (fish oil as such, fish oil-in-water emulsion and fish oil microencapsulate) for the preparation of cookies. Cookies prepared without incorporating fish oil was served as control. The physical, chemical and sensory attributes of cookies were evaluated. Encapsulation significantly (P < 0.05) decreased lipid oxidation in the cookies. The sensory evaluation of cookies showed significant (P < 0.05) difference in the overall acceptability. Results from this study, demonstrated the possibility of fish oil incorporation into cookies through emulsification and microencapsulation which may increase the intake of omega-3 fatty acids for nutritional benefits.

Developing new antioxidants and using natural examples is of current interest. This study evaluated the antioxidant activities and the ability to inhibit soybean oil oxidation of oat oil obtained with different solvents. Oat oil extract obtained by ethanol extraction gave the highest antioxidant activity with a DPPH radical (1,1-diphenyl-2-picrylhydrazyl) scavenging activity of 88.2 % and a reducing power (A 700) of 0.83. Oat oil extracted by ethanol contained the highest polyphenol and α-tocopherol content. Significant correlation was observed between the total polyphenol contents, individual phenolic acid, α-tocopherol, and DPPH radical scavenging activity. Soybean oil with 2 % added oat oil showed low malondialdehyde content (8.35 mmol mL(-1)), suggesting that the added oat oil inhibited oxidation. Oat oil showed good antioxidant activity, especially when extracted with ethanol which could also retard the oxidation of soybean oil . DPPH radical scavenging activity was the best method to evaluate the antioxidant activity and components of oat oil.

In the present study, a carbon paste electrode chemically modified with gold nanoparticles was used as a sensitive electrochemical sensor for determination of ochratoxin A. The differential pulse voltammetric method was employed to study the behavior of ochratoxin A on this modified electrode. The effect of variables such as percent of gold nanoparticles, pH of sample solution, accumulation potential and time on voltammogram peak current were optimized. The proposed electrode showed good oxidation response for ochratoxin A in 0.1 mol L(-1) PBS (pH 7.2) and the peak potential was about +0.8 V (vs. Ag/AgCl). The peak current increased linearly with the ochratoxin A concentration in the range of 0.5-100 nM. The detection limit was found to be 0.2 nM and the relative standard deviation was 6.2 % (n = 7). The method has been applied to the determination of ochratoxin A in cereal derived products such as breakfast cereals, cereal-based baby foods and beer samples.