Environmentally Friendly Approach to Pectin Extraction from Grapefruit Peel: Microwave-Assisted High-Pressure CO2/H2O.

In this research, pectin extraction from grapefruit peel (GPP) was performed using a microwave-assisted high-pressure CO2/H2O (MW-HPCO2) system. The Box-Behnken design of response surface methodology was applied for the optimization of MW-HPCO2 extraction conditions to obtain the highest pectin yield. The effects of temperature, time, and liquid/solid ratio on pectin yield were examined in the range of 100-150 °C, 5-15 min, and 10-20 mL g-1, respectively. Under the optimum extraction conditions (147 °C, 3 min, and 10 mL g-1), pectin was obtained with a yield of 27.53%. The results obtained showed that the extraction temperature and time had a strong effect on the pectin yield, while the effect of the liquid/solid ratio was not significant, and the pectin was effectively extracted from grapefruit peel (GP) using MW-HPCO2. Additionally, the application of GPP in apricot jam showed that MW-HPCO2-GPP can be used as a thickener in the food industry. The yield and physicochemical properties (ash, protein, galacturonic acid, reducing sugar and methoxyl content, degree of esterification, equivalent weight, color, viscosity) of pectin extracted in the optimum conditions of the MW-HPCO2 method were superior to pectin extracted by the traditional method. The results of this study revealed that MW-HPCO2 could be an innovative green and rapid technique for pectin extraction.

Effect of Encapsulation Techniques on Aroma Retention of Pistacia terebinthus L. Fruit Oil: Spray Drying, Spray Freeze Drying, and Freeze Drying.

The primary aim of this investigation was to assess the impact of varying the ratio of gum arabic to maltodextrin and employing diverse encapsulation techniques on the properties of the powdered substance and the capacity to retain the aromatic attributes of terebinth fruit oil. Distinct ratios of gum arabic to maltodextrin (75:25, 50:50, and 25:75) were employed to fabricate oil-in-water emulsions. The utmost stability of the emulsion was realized at a gum arabic to maltodextrin ratio of 75:25, characterized by a minimal creaming index and an even and small-scale dispersion. The encapsulation techniques employed included spray drying (SD), spray freeze-drying (SFD), and freeze-drying (FD). These methodologies were compared based on encapsulation efficiency, desiccation yield, powder attributes, and the capacity to retain aroma. The encapsulation efficiencies were notably higher (>90%) in SD, particularly with the application of an ultrasonic nozzle and a two-fluidized nozzle (2FN), in contrast to those obtained through SFD and FD. Notably, SD employing an ultrasonic nozzle exhibited superior preservation of volatiles (73.19%) compared to FD (24.45%), SD-2FN (62.34%), and SFD (14.23%). Among the various components, α-pinene and linalool stood out with near-perfect retention rates, close to 100%.

Effect of sequential-combined solar energy assisted hot air and hot air assisted radio frequency drying on the physical and chemical properties of dried apricots.

Quality characteristics of sulphured and non-sulphured apricots dried with a sequential combined pilot scale solar assisted hot air and hot air assisted radio frequency dryer and conventional sun system were compared. The combined drying approach showed improved color, hardness, antioxidant activity and retention of vitamin C, ß-carotene and total phenolic content values compared to conventional sun drying both for sulphured and non-sulphured samples. The effects of sulphur concentration and addition of pistachio hull extract as a treatment prior to drying were also investigated. Increase in sulphur concentration and addition of extract resulted in considerable quality (with respect to color, Vitamin C, ß-carotene and total phenolic content) increase in apricots. The apricots pretreated with extract had the highest total phenolic content and antioxidant activity. This study demonstrated that combined drying process is an effective drying method for apricots with the better preservation of product quality attributes.

A comparative study on performance of industrial and microwave techniques for sunflower oil bleaching process.

The main objective of this study is to compare the quality characteristics of the sunflower oils bleached with microwave and industrial techniques. The bleaching efficiencies of microwave and industrial bleaching methods were found as 83.76% and 85.68%, respectively. The totox values of bleached oil were found as 22.39 and 18.86 in microwave and industrial bleaching, respectively. The free fatty acid content was almost not changed with microwave bleaching, it was decreased by the industrial bleaching. No significant difference was reported in tocopherol content and sterol composition of oil after both industrial and microwave methods. The amount of clay and the bleaching time were reduced by 50% and 73%, respectively in microwave bleaching. The possibility of the repetitive use of bleaching clay was also evaluated and it was found that the clay used in microwave bleaching was efficient at least twice for bleaching of sunflower oil.

The effects of pectin and wax on the characteristics of oil-in-water (O/W) emulsions.

The study was aimed to investigate characteristics of emulsion containing pectin, wax, maltodextrin, and carotenoid enriched flaxseed oil by means of stability, rheology, particle size, and low-resolution of time domain nuclear magnetic resonance (NMR) relaxometry measurements. Emulsions were prepared with different carotenoid enriched-flaxseed oil concentrations (6%, 9%, 12%, and 15% w/w) and ratios of maltodextrin/(pectin+wax) (3:1, 6:1, 9:1, and 12:1 g/g). Percentage separation of 12% oil 12:1 ratio of maltodextrin/(pectin+wax) (g/g), 15% oil 9:1, and 12:1 ratios of maltodextrin/(pectin+wax) (g/g) of emulsions was determined as 2.0 ± 0.5%, 4.0 ± 0.5%, and 8.0 ± 0.5%, respectively. No separation was observed in other emulsions. The rheological behavior of emulsions was best described by the power law model. When the concentration of pectin+wax in the emulsion decreased, the n values of the emulsions were close to 1, indicating that the fluid behavior approaches Newtonian behavior. Moreover, the emulsion viscosity was observed to increase when pectin and wax concentrations in the emulsion increased. The increase in pectin and wax concentration in emulsions with oil contents of 6% and 9% resulted in a reduction in the average particle size. However, if the oil concentration in the emulsions was 12% or more, the increase in the ratio of maltodextrin/(pectin+wax) (g/g) led to a decrease in the average particle size. NMR transverse relaxation times (T2 ) of emulsions were measured and results showed that T2 values for almost all formulations decreased when the ratio of maltodextrin/(pectin+wax) reduced. PRACTICAL APPLICATION: Study results demonstrated that the combination of pectin and wax together with maltodextrin as a filling material could be an alternative way to improve emulsion stability. Findings of this study provided useful guidance for the future studies about the potential use of pectin, wax, and maltodextrin as wall material in encapsulation of oils or in producing edible films.

A Novel Modified Lipid: Enzymatic Esterification of 2-Monoacylglycerol with N-acetyl-l-leucine.

The objective of this research was to synthesize and characterize a novel modified lipid which is composed of mainly oleic acid at sn-2 position and a hydrophobic essential amino acid derivative (N-acetyl-l-leucine) at sn-1(3) or sn-1, 3 positions. LC-MS-MS analysis indicated that the target modified lipid structure was obtained at the end of the developed reaction. Response surface methodology was applied to enhance a reliable empirical model for prediction and to optimize reaction conditions: reaction time (8 to 24 hr), reaction temperature (40 to 55 °C), and enzyme load (15 to 30 wt%). The percentage of total reaction products was found to be 28.5 at the optimum conditions of 54 °C, 8 hr and 15% (by mass) enzyme load. This result is closely correlated to the predicted highest total reaction product (29.3%) obtained by response surface methodology. The physical and thermal characteristics of the modified lipid and refined olive pomace oil were compared and found to be similar. Caloric value of modified lipid was decreased by 18.65% compared to that of refined olive pomace oil. A novel modified lipid which may have potential uses in healthy food industries was successfully produced with the incorporation of N-acetyl-l-leucine to 2-monoacylglycerol. PRACTICAL APPLICATION: A novel modified lipid was synthesized by enzymatic incorporation of a "hydrophobic and essential amino acid derivative" into 2-monoacylglycerol. This modified lipid contains mainly oleic acid at sn-2 position and N-acetyl-l-leucine at sn-1,3 positions. The product behaved as an oil above 10 °C. Caloric value of the novel oil-like product was reduced by 18.65%. The modified lipid may have the potential for replacement with the oil in food products such as margarine, shortenings, salad dressing, and mayonnaise.

Valorization of Olive Pomace Oil with Enzymatic Synthesis of 2-Monoacylglycerol.

2-Monoacylglycerols (2-MAG) with a high content of oleic acid at sn-2 position was synthesized by enzymatic ethanolysis of refined olive pomace oil, which is a byproduct of olive oil processing. Six lipases from different microbial sources were used in the synthesis of 2-MAG. Immobilized lipase from Candida antarctica gave the highest product yield among the selected lipases. Response surface methodology was applied to optimize reaction conditions; time (4 to 10 h), temperature (45 to 60 °C), enzyme load (10 to 18 wt%), and ethanol:oil molar ratio (30:1 to 60:1). The predicted highest 2-MAG yield (84.83%) was obtained at 45 °C using 10 (wt%) enzyme load and 50:1 ethanol:oil molar ratio for 5 h reaction time. Experiments to confirm the predicted results at optimum conditions presented a 2-MAG yield of 82.54%. The purification yield (g 2-MAG extracted/100 g of total product) was 80.10 and 69.00 for solvent extraction and low-temperature crystallization, respectively. The purity of the synthesized 2-MAG was found to be higher than 96%.