Characterization of Beeswax and Rice Bran Wax Oleogels Based on Different Types of Vegetable Oils and Their Impact on Wheat Flour Dough Technological Behavior during Bun Making.

Five varieties of vegetable oil underwent oleogelation with two types of wax as follows: beeswax (BW) and rice bran wax (RW). The oleogels were analyzed for their physicochemical, thermal, and textural characteristics. The oleogels were used in the bun dough recipe at a percentage level of 5%, and the textural and rheological properties of the oleogel doughs were analyzed using dynamic and empirical rheology devices such as the Haake rheometer, the Rheofermentometer, and Mixolab. The thermal properties of beeswax oleogels showed a melting peak at a lower temperature for all the oils used compared with that of the oleogels containing rice bran wax. Texturally, for both waxes, as the percentage of wax increased, the firmness of the oleogels increased proportionally, which indicates better technological characteristics for the food industry. The effect of the addition of oleogels on the viscoelastic properties of the dough was measured as a function of temperature. All dough samples showed higher values for G' (storage modulus) than those of G″ (loss modulus) in the temperature range of 20-90 °C, suggesting a solid, elastic-like behavior of all dough samples with the addition of oleogels. The influence of the beeswax and rice bran oleogels based on different types of vegetable oils on the thermo-mechanical properties of wheat flour dough indicated that the addition of oleogels in dough recipes generally led to higher dough stability and lower values for the dough development time and those related to the dough's starch characteristics. Therefore, the addition of oleogels in dough recipes inhibits the starch gelatinization process and increases the shelf life of bakery products.

Structural, functional and physicochemical properties of pectin from grape pomace as affected by different extraction techniques.

Pectin from grape pomace (Vitis vinifera var. Feteasca Neagra and Vitis vinifera var. Rara Neagra) was extracted by using different extraction techniques (conventional, microwave-assisted and pulsed ultrasound-assisted extraction). Microwave-assisted extraction showed highest yield (11.2 %) for Rara Neagra pectin, while conventional extraction presented highest yield (9.9 %) for Feteasca Neagra pectin. The yield was directly correlated with the galacturonic acid content, degree of esterification, molecular weight and functional features (water-holding, oil-holding and water-swelling capacity, emulsifying properties and rheological behavior of pectin emulsions). In addition, the FT-IR, morphological structure, thermal analysis and emulsion properties of obtained pectin samples from different extraction techniques revealed dissimilar results by comparing with commercial pectin.

Characterization of Babeasca Neagra Grape Pomace and Incorporation into Jelly Candy: Evaluation of Phytochemical, Sensory, and Textural Properties.

The influence of particle size intervals (<125 µm, ≥125-<200 µm, and ≥200-<300 µm) of grape pomace (Vitis vinifera var. Babeasca Neagra) was analyzed in terms of the proximate composition, functional properties, and physicochemical parameters. The aim was to study the effect of the formulation variables (extract from grape pomace with different particle size intervals and gelatin doses-7, 8.5, and 10 g) on the mechanical properties (hardness, cohesiveness, adhesiveness, springiness, and gumminess), color, and sensorial, microbiological, and phytochemical parameters. The jelly candy formulated with grape pomace extract (<125 µm) and 7 g of gelatin showed the highest total phenolic content (156 mg GAE/g) and antioxidant activity (65.8% inhibition), while grape pomace jellies with a particle size of ≥125-<200 µm and different concentration of gelatin presented the greatest sensory acceptance in terms of sweetness, taste, odor, elasticity, color, and overall acceptability of the resulting jelly. The concluding observation was supported by the microbiological analysis, which also showed that there is no growth in jelly samples except the jelly candies prepared with a ≥200-<300 µm particle size interval of grape pomace extract.

Characterization of Pectin from Grape Pomace: A Comparison of Conventional and Pulsed Ultrasound-Assisted Extraction Techniques.

The yield, physicochemical and rheological parameters of grape pomace pectin (Feteasca Neagra and Rara Neagra) obtained by conventional extraction (CE) were compared to those acquired by pulsed ultrasound-assisted extraction (PUAE). Extraction temperature (70-90 °C), pH (1-3) and time (1-3 h) were considered as independent variables for CE, while amplitude (20-100%), pH (1-3) and time (20-60 min) for PUAE. The optimal conditions for maximum yield and physicochemical parameters of pectin samples extracted by CE were temperature of 90 °C, pH 1.9 for 164 min (9.96% yield, 79.91 g/100 g of galacturonic acid (GalA) content, 81.28% of degree of esterification (DE) and 5.52 × 104 g/mol of molecular weight (Mw) for Feteasca Neagra (FN) pectin; 11.08% yield, 80.05 g/100 g of GalA content, 80.86% of DE and 5.59 × 104 g/mol of Mw for Rara Neagra (RN) pectin), while for PUAE they were amplitude of 100%, pH 1.8 for 60 min (8.83% yield, 80.24 g/100 g of GalA content, 81.07% of DE and 4.19 × 104 g/mol of Mw for FN pectin; 8.94% yield, 78.64 g/100 g of GalA content, 80.04% of DE and 4.23 × 104 g/mol of Mw for RN pectin). The yield and physicochemical parameters of CE pectin were higher than PUAE pectin. The FT-IR spectra of pectin samples revealed the occurrence of polysaccharide compound, while rheology characteristics confirming its application in different food products.

Microwave-assisted extraction of pectin from grape pomace.

The utilization of microwave technique for the pectin extraction from grape pomace (Feteasca Neagra and Rara Neagra), its influence on yield, galacturonic acid content, degree of esterification and molecular weight of pectin were analyzed. The optimal conditions of the extraction process were microwave power of 560 W, pH of 1.8 for 120 s. The pectin samples extracted by MAE in optimal conditions were analyzed by comparing with commercial apple and citrus pectin based on FT-IR analysis, thermal behavior, rheological characteristics and microstructure. The FT-IR analysis established the presence of different functional groups which are attributed to the finger print region of extracted pectin, while the rheological behavior presented a good viscoelasticity of pectin solutions. The obtained data assumes that grape pomace has a great potential to be a valuable source of pectin which can be extracted by simple and quick techniques, while maintaining analogous quality to conventional sources of pectin.

The Influence of Extraction Conditions on the Yield and Physico-Chemical Parameters of Pectin from Grape Pomace.

Grape pomace is one of the most abundant by-products generated from the wine industry. This by-product is a complex substrate consisted of polysaccharides, proanthocyanidins, acid pectic substances, structural proteins, lignin, and polyphenols. In an effort to valorize this material, the present study focused on the influence of extraction conditions on the yield and physico-chemical parameters of pectin. The following conditions, such as grape pomace variety (Feteasca Neagra and Rara Neagra), acid type (citric, sulfuric, and nitric), particle size intervals (<125 µm, ≥125−<200 µm and ≥200−<300 µm), temperature (70, 80 and 90 °C), pH (1, 2 and 3), and extraction time (1, 2, and 3 h) were established in order to optimize the extraction of pectin. The results showed that acid type, particle size intervals, temperature, time, and pH had a significant influence on the yield and physico-chemical parameters of pectin extracted from grape pomace. According to the obtained results, the highest yield, galacturonic acid content, degree of esterification, methoxyl content, molecular, and equivalent weight of pectin were acquired for the extraction with citric acid at pH 2, particle size interval of ≥125−<200 µm, and temperature of 90 °C for 3 h. FT-IR analysis confirmed the presence of functional groups in the fingerprint region of identification for polysaccharide in the extracted pectin.

The Potential of Grape Pomace Varieties as a Dietary Source of Pectic Substances.

Grape pomace is one of the most abundant solid by-products generated during winemaking. A lot of products, such as ethanol, tartrates, citric acid, grape seed oil, hydrocolloids, bioactive compounds and dietary fiber are recovered from grape pomace. Grape pomace represents a major interest in the field of fiber extraction, especially pectin, as an alternative source to conventional ones, such as apple pomace and citrus peels, from which pectin is obtained by acid extraction and precipitation using alcohols. Understanding the structural and functional components of grape pomace will significantly aid in developing efficient extraction of pectin from unconventional sources. In recent years, natural biodegradable polymers, like pectin has invoked a big interest due to versatile properties and diverse applications in food industry and other fields. Thus, pectin extraction from grape pomace could afford a new reason for the decrease of environmental pollution and waste generation. This paper briefly describes the structure and composition of grape pomace of different varieties for the utilization of grape pomace as a source of pectin in food industry.

The influence of osmotic treatment assisted by ultrasound on the physico-chemical characteristics of blueberries (Vaccinium myrtillus L.).

The aim of the study was to analyse the effect of osmotic treatment assisted by ultrasound on the physico-chemical properties of blueberries from Suceava county, Romania. Ultrasound treatment was conducted at the frequency of 25 kHz (using different values of amplitude - 20, 60 and 100%, respectively) in 61.5% sucrose solution at 30, 40 and 50 °C for 20, 40 and 60 min. The Box-Behnken design was used to investigate the influence of independent variables (time, temperature and amplitude) on the osmotic dehydration. The results showed that for physico-chemical characteristics (mass transfer parameters; moisture content; total content of anthocyanins, flavonoids and polyphenols; DPPH assay scavenging activity) that optimal conditions were obtained at 30 °C for 40 min at a 100% amplitude. Ultrasound treatment stimulated changes in the main characteristics, especially of colour leading to a higher lightness (L*), decreasing AsA-POD and water activity. The results indicated that the higher the values of independent variables are, the more representative is the correlation between them.