Development and Validation of the HPLC Method for Simultaneous Quantification of Glucose and Xylose in Sugar Cane Bagasse Extract.

A validated rapid high-performance liquid chromatography (HPLC)-refractive index (RI) method was developed for the identification and quantification of glucose and xylose in hydrolyzed bagasse extract. The separation of compounds was achieved on Eurokat® H column (300 × 8 mm, 10 µm) at 75°C, using 0.01 N sulfuric acid solution as mobile phase and 0.6 mL/min as flow rate. The method was validated based on accuracy, precision, linearity, robustness, uncertainty, limit of detection (LOD) and limit of quantification (LOQ). Total chromatographic analysis time per sample was ~11 min. Calibration plots were linear over the concentration ranges 11-100 µg/100 µL for glucose and xylose. The LOD was 0.8 ppm and LOQ was 2.5 ppm. The high recovery and low relative standard deviation confirm the suitability of the method for determination of glucose and xylose in bagasse extract. The proposed HPLC-RI method was accurate, fast and robust and required less run time due to less analytes retention times and allowed optimal energy consumption owing to lower column oven temperature.

Enhancing the accuracy, speed, and efficiency of kafirin-PEO electrospun bio-nanocomposite pH indicators with red beetroot extract using image processing.

Intelligent electrospun pH indicators were produced from bio-nanocomposite kafirin-polyethylene oxide (PEO) containing red beetroot extract. The aim was to evaluate the performance and stability of the electrospun pH indicators via image processing. Red beetroot extract was added to a mixture of kafirin and PEO at various concentrations. The mixtures were electrospun, and infrared Fourier transform spectroscopy confirmed the presence of kafirin, PEO, and red beetroot extract in the resulting pH indicator. The results showed that the pH indicators had high stability and reversibility at different temperatures, pHs, and environmental conditions. The results showed that the color of the indicators was significantly reversible after pH changes, with highly desirable reversibility observed at pH values of 1, 3, 4, 5, 7, 9, and 10. The findings proved that the red beetroot extract loaded bio-nanocomposite pH indicator accompanied by evaluation of color characteristics through image processing technique, can serve as a time-efficient, accurate tool for detecting and tracking pH changes caused by food spoilage.

Thermal processing of pomegranate seed oils underscores their antioxidant stability and nutritional value: Comparison of pomegranate seed oil with sesame seed oil.

In the present study, the oxidative stability and antioxidant activity of seed oils were investigated in three Iranian pomegranate cultivars, Shirin Khafr, Torsh Sabz, and Rabab, along with the sesame (Sesamum indicume L. cv Dezful) seed oil. Punicic acid was the primary fatty acid in the pomegranate seed oils, with contents ranging from 75.5 to 80.9% (w/w). The tocopherol levels in pomegranate seed oils ranged from 1439 to 2053 mg/kg, whereas the phenolics ranged from 130 to 199.3 mg/kg, respectively. Comparatively, in the seed oil of sesame "Dezful," these substances' contents were 1053 and 79 mg/kg, respectively. Contrary to common perception, the seed oil of the three pomegranate cultivars cultivated in Iran had high oxidative stability and antioxidative activity during the 32 h of thermal processing at 170°C. The oxidation stability assayed by peroxide value, p-anisidine value, and TOTOX index revealed that the pomegranate seed oils had a much higher resistance to the oxidation process than the sesame oil. The content of tocopherols increased during thermal processing due to the regeneration phenomenon. Tocopherols are not always free and may form a matrix with themselves or other compounds. Changes in the antioxidant activity during the thermal processing assessed by DPPH free radical scavenging power and by the FRAP test were consistent with those for the antioxidants. Therefore, these oils can be added to other edible oils as a natural antioxidant to improve their oxidative stability.

Fabrication and characterization of bio-nanocomposites based on kafirin and polyethylene oxide as auxiliary polymer: process optimization, rheological, morphological and thermal properties.

The aim of this research was to compare the effects of various solvents on producing kafirin/polyethylene oxide (PEO) bio-nanocomposites by the technique of electrospinning. Different concentrations of kafirin (15, 20, 25, 30 and 40% w/v) and PEO (2, 4 and 6% w/v) were electrospun. For the dissolution and electrospinning of these two biopolymers, different solvents were used comparatively, i.e. distilled water, ethanol (70%), acetic acid (40%), 2-Butanol and glacial acetic acid. An evaluation of flow behavior showed that kafirin and PEO had Newtonian and pseudoplastic behaviors, respectively. A mixture of these two polymers demonstrated quasi-Newtonian and shear-independent behaviors in a low shear rate range, which positively affected the electrospinning process. SEM images showed that the best concentrations of kafirin and PEO were 25 and 2%, respectively, for producing nanofibers with uniform structures. Fourier-transform infrared spectroscopy (FTIR) indicated the presence of kafirin and PEO in the bio-nanocomposite after electrospinning. The FTIR proved that these two polymers had no chemical interactions with each other. Overall, the results showed that selecting an appropriate solvent and a suitable auxiliary polymer could have significant roles in producing biodegradable kafirin nanofibers.

Potential application of modified date powder by microwave radiation, ultrasonication and chemical pretreatments as coffee substitute: its biochemical properties and consumer preferences.

To consider the suitability of modified date powder as a coffee substitute, the biochemical and antioxidant properties of date powder were modified by hydrochloric acid-ethanol (HAE), alkaline hydrogen peroxide (AHP), combined with ultrasound (U) microwave (MW) radiation. The results showed that the highest antioxidant activity was observed in HAE and HAE-U treated date powders. The total flavonoid content of the date powder increased by 40.8% and 100% in response to the AHP-MW and HAE-U treatments, respectively. Fourier transform infrared spectroscopy did not show any abnormal or unknown peaks in the analyzed range of the treated samples. Therefore, modification of biochemical and sensory properties of date powder by chemical and irradiation treatments did not have a detrimental effect on changing the structure of its chemical compounds or the formation of harmful compounds in it. Sensory evaluations showed that replacing coffee powder with modified date powder by up to 25% did not have significant effects on the sensory properties of the coffee drink. Finally, the results showed that modifying the biochemical and antioxidant properties of date powder by the HAE method as coffee substitute can increase the nutritional properties of coffee drinks while also reducing the expenses of the coffee industry.

Influence of ß-glucan extracted from hull-less barley on droplet characterization, stability and rheological properties of soy protein isolate stabilized oil-in-water emulsions.

In this study the effect of ultrasonically extracted ß-glucan from hull-less barley (UBG, 0.25-0.75% w/w) on soy protein isolate (SPI, 4-12% w/w) stabilized oil-in-water emulsions was investigated. The results indicated that with increasing UBG concentration, zeta potential, droplets' specific surface area and emulsion stability increased; whereas, the surface and interfacial tensions, Sauter mean diameter (D3,2) and the De Brouckere Mean Diameter (D4,3), span value and creaming index decreased. Non-Newtonian shear-thinning (pseudoplastic) behavior was observed for oil-in-water emulsions stabilized by UBG. With increase in UBG and SPI concentrations, emulsion's flow behavior index (n) and consistency coefficient (k) increased and decreased; respectively. At all UBG and SPI concentrations, emulsions stored at 4 °C were more stable.

Phytochemical profiles of lemon verbena (Lippia citriodora H.B.K.) and its potential application to cookie enrichment.

In this research, phytochemical properties of lemon verbena and oxidative stability of the fat component in cookies (contain lemon verbena powder and EO) were investigated. The essential oil (EO) profile and polyphenol compounds were identified by GC/MS and HPLC, respectively. Different concentrations of lemon verbena powder and EO were added to the cookies in comparison with TBHQ. The oxidative stability of fat component in cookies (peroxide value, p-Anisidine, TOTOX value), along with the physicochemical (pH, acidity, weight loss, and moisture content) and sensory properties of the cookies were evaluated over a period of 6 months during storage at room temperature. The main constituents of EO are geranial (27.21%), neral (20.01%), spathulenol (7.28%), and limonene, while trans-Ferulic acid (6.71 mg/g), Hesperidin (1.87 mg/g), and ρ-Coumaric acid (0.04 mg/g) were measured as main phenolic compounds. The peroxide value increased in all samples for the first 2 months of storage and then decreased as hydroperoxide was converted to secondary oxidation products. The p-Anisidine value increased in all samples during storage. This parameter was lower in cookies containing lemon verbena EO and TBHQ treatments. Sensory evaluations of cookies showed that lemon verbena EO had positive effects on the aroma and taste of cookies during storage, whereas lemon verbena powder had adverse effects on mouthfeel and consumer acceptance. The results showed that lemon verbena can increase the eating quality, prolong the shelf life, and maintain the integrity of bakery products with high-fat content.

Kinetic studies on palm heart protein solubility and investigation of physicochemical, functional and thermal properties of palm heart protein isolate.

The chemical composition of palm heart (cultivar Piarom) and solubility kinetics of its protein was investigated under different salt concentrations and pHs. Palm heart protein isolate (PHPI) was prepared using alkaline extraction and acidic precipitation and its functional properties (emulsifying properties and emulsion stability, foam capacity, and water holding and fat absorption capacity) and thermal properties were determined. It was revealed that palm heart had high nutritional value and contains high protein content. By increasing pH up to 3, solubility was decreased and then significantly increased by elevating pH to 9 (p < 0.05). Salt addition significantly decreased palm heart protein (PHP) solubility. Considering solubility kinetics, pH 9 and salt concentration of 0.25 M was determined as the best protein extraction condition. Denaturation temperature and enthalpy changes of PHPI were 108.63 °C and 143.1 J/g; suggesting high thermal stability of this product. Regarding its suitable functional, physicochemical and thermal properties, PHP can be considered as an ideal substitution for animal protein sources in the food industry.

Ultrasound-assisted extraction of ß-d-glucan from hull-less barley: Assessment of physicochemical and functional properties.

The present study was carried out to investigate the effect of ultrasound-assisted extraction (UAE) method on physicochemical and molecular properties of hull-less barley ß-d-glucan. With increasing sonication time, ß-d-glucan flow behavior index (n) and its extraction yield significantly increased while its consistency coefficient and lightness decreased. Sonication time had no significant effect on ß-d-glucan purity, emulsion and foam stabilizing effect and colour. Increasing pH from 5 to 9 significantly enhanced extraction yield, purity, consistency coefficient (k), emulsion stabilizing effect and yellowness of the final product. At higher pHs, flow behavior index (n) and redness and yellowness decreased. With increasing the amplitude, extracted ß-d-glucan flow behavior index (n), redness significantly increased. In contrast, ß-d-glucan purity, emulsion stability, consistency coefficient (k) and yellowness decreased as a result of increase in sound amplitude. However, sound amplitude had no significant effect on ß-d-glucan lightness. Models presented in this study were highly significant and the correlation coefficient could be used for optimization of ß-d-glucan extraction from hull-less barley. Considering the importance and desirability of the response variables, the best results were obtained when the sonication time, amplitude and pH were 4.8min, 50% and 9, respectively. ß-d-Glucans extracted by UAE had lower average molecular weight compared to those extracted by water extraction method. There was no difference between the chemical structures of ß-d-glucans extracted by UAE and conventional method. This means that short time ultrasonic extraction had no effect on chemical structure of ß-d-glucan. These results indicate that UAE method was a very effective tool for extraction of ß-d-glucan as a potential hydrocolloid agent for food industries.