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BACKGROUND The effect of the addition of hydroxypropyl methylcellulose ( HPMC) on the textural properties of low-fat tofu was investigated. Three fat levels (240, 100 and 30 g kg−1) were used to make tofu, which were identified as C (full-fat tofu), L1 and L2. HPMC (5 g kg−1) was added to soymilk to prepare control and low-fat tofu, designated as CH, L1H and L2H. RESULTS Soymilk with a lower fat level had a lower viscosity: 143 (C), 100 ( L1) and 42 ( L2) cP. The addition of HPMC increased the viscosity of all types of soymilk, particularly in L2H (107 cP). With fat reduction, tofu syneresis increased from 19% (C) to 29% ( L2), although syneresis of L2H recovered to 19%, which is similar to high-fat control tofu. Decreased fat resulted in a lower firmness in L2 (0.67 N) compared to control (0.78 N). Firmness increased to 1.08 N in L2H tofu, whereas the firmness of CH tofu was 0.63 N. All types of tofu showed a denser, well-connected and cross-linking structure when HPMC was added, especially in L2H tofu. CONCLUSION HPMC improved the texture of the low-fat tofu by creating a harder texture and reducing syneresis. HPMC is an effective fat replacer for lower fat soymilk. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The physical stability of oil-in-water emulsions containing β-carotene was investigated to assess the emulsification of three hydroxypropyl methylcellulose (HPMC) of varying substitution and viscosity and gum acacia (GA) control dispersions. Initially, emulsions stabilized with GA had particle sizes of 0.79 μm, whereas the HPMC stabilized emulsions possessed particle sizes of about 1.38–1.96 μm. Following storage at 25 °C or 37 °C for up to 12 days, no significant differences between the initial and final particle sizes for two of the three HPMC stabilized emulsions (P < 0.05) were observed and remained <2.0 μm. However, the particle size distributions changed with time of storage at 25 °C or 37 °C in all emulsions, but were minimal in the emulsion containing the highest initial viscosity HPMC (0.401 Pa s). Images from light microscopy demonstrated that variability in droplet sizes was more prominent in low viscosity, low M:HP HPMC stabilized emulsions. Small amplitude oscillatory shear measurements revealed that the HPMC that possessed a viscosity of 0.401 Pa s and high M:HP (4.45) displayed characteristics of a weak gel network, which likely provided additional resistance against particle size increase. The analysis of the data demonstrates that HPMC with high viscosity, high M:HP produce emulsions with greater physical stability. [ABSTRACT FROM AUTHOR]

Abstract: The interaction of non-fat dry milk, caseinate and casein (CSN) fractions with charge modified pectins (B-Pec and U-Pec) and unmodified pectin (O-Pec) in acidified dispersion systems was investigated. U-Pec led to more precipitation of proteins than O-Pec or B-Pec. Casein dispersions with pectin had larger particle size, especially U-Pec and B-Pec, than dispersions without pectin. Dispersions with charge modified pectins showed more negative ζ-potential than dispersions with unmodified pectin or dispersions without pectin. U-Pec enhanced negative ζ-potential of β-CSN more than B-Pec. There was no significant difference in flow behavior among non-fat milk samples regardless of pectins added. In contrast, non-Newtonian behavior, shear thinning behavior was observed in modified pectin added κ-CSN. Analysis by light microscopy of non-fat milk and κ-CSN showed that sizes and shapes were changed by addition of O-Pec and U-Pec. The results suggest a specific affinity between pectin and κ-CSN, which is related to the charge distribution of pectin. [ABSTRACT FROM AUTHOR]

Abstract: Pectin was de-esterified by U-PME or B-PME, pectinesterases that differed in cationic character and peptide composition. Pectin fractions of unmodified (O-Pec) and Valencia PME modified pectins (B-Pec and U-Pec) were separated by ion exchange (IEX) chromatography and characterized for calcium sensitivity by ζ-potential, texture profile analysis (TPA), and viscoelastic properties. U- and B-Pec had more negative ζ-potential than O-Pec, and became increasingly negative at higher pH values. Without CaCl2, viscosity of O-Pec was higher than B- and U-Pec. With 35mM CaCl2, B- and U-Pec gelled, but O-Pec did not gel. TPA values were not significantly different between B-Pec and U-Pec. The G'' values of O-Pec was 20–50-fold lower than G'' for B-Pec or U-Pec. After separation with ion exchange chromatography, later eluting fractions formed stronger gels than earlier eluting fractions. However, pectin fractions had lower viscosity and G'' values than unfractionated pectin, which is likely related to molecular weight differences. Results show that U-Pec forms stronger gels than B-Pec that is related to length of charge block and numbers of de-esterified pectin molecules. [Copyright &y& Elsevier]

Pectins from highbush blueberry powder were sequentially solubilized in water, chelator, and sodium carbonate solvents and precipitated (ADF.WSF, ADF.CSF, and ADF.NSF) or not precipitated in ethanol (DF.WSF, DF.CSF, and DF.NSF) before dialysis and freeze‐drying. Alcohol precipitation more effectively removed bound anthocyanins and low molar mass pectins from water‐ and chelator soluble fractions than dialysis alone. Blueberry water soluble fractions were high methoxyl pectins, rich in neutral sugars (36 to 38 mol%), and had high molar mass (7.01 × 105 to 2.71 × 106 g/mol). Blueberry chelator soluble fractions were low methoxyl pectins and rich in uronic acids (90 to 92 mol%) which were more linear and less branched structure than other fractions or commercial citrus pectin. The molar mass ranged from 1.59 × 106 to 2.06 × 106 g/mol. Water‐ and chelator soluble fractions exhibited pseudoplastic behavior (n < 1) at 1% dispersion. Blueberry sodium carbonate soluble fractions were rich in protein (18%) and neutral sugars (42 to 28 mol%), and had low molar mass (1.08 × 105 to 1.27 × 105 g/mol). Blueberry pectins have desirable physico‐chemical properties for use as functional ingredients in food or beverages. Practical Application: Alcohol precipitation effectively removed anthocyanins from the pectin. The characterization data provided the benefits of blueberry pectin as a functional ingredient. This study can be used by food or product developers who are interested in pectin from blueberries or other berry products. [ABSTRACT FROM AUTHOR]

Husk tomato ( Physalis ixocarpa Brot. var. Rendidora) waste was evaluated as a source of specialized pectin, and pectin extracted from this waste was characterized physicochemically. Fruit was blanched for 10 or 15 min and extracted in 0.1 N HCl for 15 to 25 min. Extracted pectin was subjected to physicochemical analysis. For all extraction conditions, the percentage of anhydrogalacturonic acid exceeded 60%, indicating that husk tomato was a good source of pectin. The degree of esterification of pectin molecules was 63% to 91%. The amount of extracted pectin decreased with increasing extraction time. The apparent viscosity of husk tomato pectin showed the characteristic behavior of pseudoplastic fluids. Neutral sugars were identified, and the amounts of 6 sugars (fucose, rhamnose, arabinose, galactose, glucose, and xylose) were quantified. Sugars identified in husk tomato pectin and present in the Rhamnogalacturonan I region, arabinose, galactose, and rhamnose suggest a highly branched structure, which will influence its future applications. Molecular weight values were 542 to 699 kDa, exceeding molecular weight values reported for commercial citrus pectins from 134 to 480 kDa. The extraction process significantly ( P < 0.05) influenced the physicochemical properties of pectin. Up to 19.8% from the total amount of pectin in the husk tomato was extracted by 10 min of blanching and 20 min of a more heat treatment. Our findings indicate that husk tomato can be a good alternative source of pectin having highly distinctive physicochemical characteristics. [ABSTRACT FROM AUTHOR]

BACKGROUND Preventing post-harvest waste of Palmyra palm ( Borassus aethiopum Mart.) fruits is possible by recovery of pectin as a value-added ingredient. Extraction conditions on yield and functionality of Palmyra palm pectin was determined at different temperatures and pH values with 30 min extraction time. RESULTS Palmyra palm fruits contain more than 650 g kg−1 galacturonic acid and produce soft gels with sucrose in acidic media despite a high degree of acetylation (∼5%). Mechanical deformation of pectin gel was similar when extracted at pH 2.5 and 70 °C or under natural pH at room temperature or 70 °C. Pectins isolated at pH 7 exhibited comparable gel softness ( G′/ G″) with commercial pectin. Palm pectins also showed emulsifying activity greater than 50%, attributed to high protein content of 8 g 100 g−1. For pectins extracted at pH near 5.2-5.5, molar mass ranged from 3.00 to 3.38 × 105 g mol−1; intrinsic viscosity ranged from 218 to 297 mL g−1; arabinose was the main neutral sugar; ζ-potential ranged from −23 to −25 mV. CONCLUSION Palm fruit offers an inexpensive raw material to extract pectin in environmentally friendly and economical way and yield a pectin with unique gelling, viscosifying and emulsifying properties. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Large numbers of fruits from Palmyra palm ( Borassus aethiopum Mart), a common, native tree of tropical regions, are underutilized and left to spoil. This work was conducted to assess pectin content of Palmyra palm fruit, and to develop a reliable protocol for pectin extraction. Yield and galacturonic acid content of Palmyra palm fruit soluble solids were investigated at various pH (natural pH of 5.2–5.5, 2.5, 7), time (30–120 min) and temperature (70 °C, 80 °C, 90 °C). Yield and galacturonic acid content of extracted soluble solids were strongly dependent (p < 0.0001) on temperature, time and pH of extraction and ranged from 47 to 149 g kg−1 and 682 to 880 g kg−1 dry weight, respectively. High galacturonic acid (808–852 g kg−1) were obtained at 70 °C and 90 °C under natural pH; at 70 °C pH 7 and pH 2.5 at all temperatures studied. Analysis of pectin extracted at natural pH (30 min, 90 °C) revealed highly esterified pectin with good gelling and emulsifying properties. Production of galacturonic acid of more than 650 g kg−1 dry weight indicates that Palmyra palm fruit could serve as an excellent raw material for industrial pectin production. [ABSTRACT FROM AUTHOR]