Classification and physicochemical characterization of mesquite gum (Prosopis spp.)

Under environmental stress conditions, mesquite trees can excrete a proteinaceous arabinogalactan gum that is similar to gum arabic. Given the application potential of this type of gums a classification procedure for the mesquite gum is proposed. The main physicochemical properties of the best-quality mesquite gum were determined and compared with those of gum arabic. Additionally, the composition and molecular changes induced by purification processes were recorded. One batch (157 kg) of mesquite gum was categorized by subjective assessment into three classes (MGA, MGB and MGC) from high- to low-quality. Approximately 17.5% was classified as top-quality gum. It was found that this class of mesquite gum has lower humidity, inorganic and tannins content than the other classes, or even than the gum arabic sample used as a reference. All of the mesquite gum classes have higher protein content and lower intrinsic viscosity than gum arabic. The purification processes were shown to reduce the content of lower molecular weight compounds that modify the interface properties of the gum. The results indicate that the proposed classification method can be used to select mesquite gum with physicochemical properties comparable to those of commercial gum arabic.     

NMR study of galactomannans from the seeds of mesquite tree (Prosopis juliflora (Sw) DC)

The seed gum from Prosopis juliflora is a galactomannan polysaccharide, which is located in the endosperm. Regarding P. juliflora galactomannan structural studies, there are reports on galactose substitutional pattern, but supporting data by NMR correlation studies are scarce. In this work, a procedure to obtain P. juliflora gum without contamination was employed and the gum was studied by NMR spectroscopy. Overall, results show that mesquite seed has a 1.1:1 Man/Gal ratio.     

Physicochemical properties of a fibrous fraction from chia (Salvia hispanica L.)

An evaluation was done of some physicochemical properties of a fiber-rich fraction (FRF) obtained by dry processing of defatted chia (Salvia hispanica) flour. The fiber-rich fraction (FRF) had 29.56 g/100 g crude fiber content and 56.46 g/100 g total dietary fiber (TDF) content, of which 53.45 g/100 g was insoluble dietary fiber (IDF) and 3.01 g/100 g was soluble dietary fiber (SDF). The FRF water-holding capacity was 15.41 g/g, its water absorption capacity 11.73 g/g, and its organic molecule absorption capacity 1.09 g/g. The FRF also had low oil-holding (2.02 g/g) and water adsorption (0.3 g/g) capacities. Emulsifying activity in this fraction was 53.26% and emulsion stability was 94.84%. Its evaluated antioxidant activity was 488.8 μmol/L Trolox equivalents/g FRF, which is higher than for many cereals and similar to drinks such as wine, tea, coffee and orange juice. The chia FRF values for the evaluated properties, particularly for water-holding, oil-holding and organic molecule absorption capacity, suggest it could be a useful ingredient in dietetic products such as baked and fried foods, among others.     

Chemical composition and functional properties of Gleditsia triacanthos gum

The seeds of Gleditsia triacanthos (Fabaceae) are a source of galactomannans with a variable mannose:galactose (Man:Gal) ratio that depends on the isolation and purification methods. In this study, three processes were used: (1)—treatment with boiling water (M1); (2)—concentration with boiling 2 N NaOH (M2) and (3)—swelling with water and later manual removal of the endosperm (M3). The functional properties of the hydrocolloids obtained by the three isolating methods were compared with those exhibited by xanthan and guar gums, which are widely used as food additives. The product obtained by boiling water (M1) had the lowest yield, although that hydrocolloid showed high water absorption capacity and solubility, high emulsifying and foaming capacities, and imparted high stability to the dispersions (foams and emulsions). These properties could be influenced by its high Man:Gal ratio and protein content.     

Physicochemical and functional properties of the protein isolate and major fractions prepared from Akebia trifoliata var. australis seed

The physicochemical and functional properties of protein isolate (API) and major protein fractions prepared from Akebia trifoliata var. australis seed were investigated. The seed contained 38.83% of oil and 17.23% of protein. Albumin (51.65%) and glutelin (46.40%) were the predominant fractions in the protein component of the seed. The major amino acids were found to be glutamic acid and aspartic acid, while the contents of sulphur-containing amino acids and threonine were very low. One to eight distinct bands with molecular weight (MW) ranging from 12.0 to 50.0 kDa were displayed by SDS–PAGE. The solubilities of API, albumin and glutelin from seeds of the A. trifoliata var. australis were the lowest at pH 4.0–5.0. The high surface hydrophobicity indices of these three proteins were observed at pH 7.0, while the excellent emulsifying properties were displayed at pH 9.0. Circular dichroism measurements indicated that API, albumin and glutelin were rich in β-strand and random coil structures.     

Physicochemical and functional properties of makal (Xanthosoma yucatanensis) starch

Physicochemical and functional properties of makal (Xanthosoma yucatanensis) starch were determined. Granules were oval in shape and 12.4 μm average diameter. Starch purity was high (96.7%) with low protein (0.1%), fat (0.2%), fibre (0.4%) and ash (0.1%) contents. Amylose content was 22.4%. The gelatinization temperature was 78.5 °C and transition enthalpy was 15 J/g. At 90 °C, solubility was 32.9%, swelling power was 28.6 g water/g starch and water absorption capacity was 19.2 g water/g starch. Pasting characteristics were: temperature 75 °C, maximum viscosity 280 BU, breakdown −8 BU, setback 180 BU and consistency 172 BU. Clarity, expressed as transmittance, was 35.8%. Gel deformation was 20.8% with a 0.03 kgf maximum load. Makal starch’s high gelification temperature and firmness make it appropriate for use in high temperature food systems, but its low stability in refrigeration and freezing cycles make it inadequate for use in foods subject to those conditions.     

Antioxidant Parkia speciosa pod powder as potential functional flour in food application: Physicochemical properties’ characterization

Chemical, physicochemical and functional properties of fibrous materials from freeze dried (FDPSP) and oven dried (ODPSP) Parkia speciosa pod (PSP) were evaluated in order to examine the potential applications in food. Preliminary screening of PSP using scanning electron microscope showed that PSP consisted of starches and fibres. Proximate analysis showed that both samples consisted of 4.3–5.2% of moisture, 9.5–10.7% of protein, 0.1–0.2% of fat, 0.01% of ash, 16.5–16.8% of crude fibre and 68.3–68.7% of carbohydrates. However, different functional properties were shown in these samples. FDPSP gave a lighter colour compared to ODPSP. Higher values of solubility (30.8%), water- and oil-holding capacities (3.72 and 1.55 g/g, respectively) were found in FDPSP. Conversely, higher emulsifying activity of 62.7% with high emulsion stability of 99.9% was shown in ODPSP. Higher antioxidative properties were also shown in FDPSP which consist TPC of 110.0 mg gallic acid equivalent/g sample and TFC of 8.5 mg pyrocatechol equivalents/g sample. These extracts (pre-diluted 50×) gave %DPPH_sc, %ABTS_sc and FRAP values of 65.3%, 77.4% and 1.9 mM FeSO₄, respectively. Therefore, it was suggested that PSP has the potential in producing functional fibres that could be imparted into the food system.     

Physicochemical characterization of chitosan extracted from Metapenaeus stebbingi shells

In this study, chitosan was extracted from Metapenaeus stebbingi shells. In order to determine physicochemical characteristics of the extracted chitosan, the yield, moisture and ash contents, degree of deacetylation, molecular weight, water and fat binding capacities, apparent viscosity and colour properties were measured using a variety of techniques including Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction. In addition, the physicochemical characteristics of the chitosan extracted from M. stebbingi shells were compared to commercial chitosan. The degree of deacetylation was calculated by the titration method and elemental analysis. The molecular weight was determined by viscosimetric methods. The results of the study indicate that shrimp shells are a rich source of chitosan as 17.48% of the shell’s dry weight is consisted of this material. Extracted chitosan exhibited a lower molecular weight, higher degree of deacetylation, higher viscosity and higher water and fat binding capacities compared to the commercial chitosan.     

Physicochemical characteristics and functional properties of grape (Vitis vinifera L.) seeds protein

The amino acid composition, physicochemical and functional properties of grape (Vitis vinifera L.) seeds protein (GSP) were evaluated and compared with those of soybean protein isolate (SPI). Amino acid analyses of GSP revealed high levels of glutamic/glutamine, glycine and aspartic/asparagines. SDS‐PAGE analysis demonstrated that globulin was the major protein component in GSP, whose subunit molecular weights were mainly varied from 25.5 to 40.0 kDa. The isoelectric pH of GSP was found to be at the acidic pH of around 3.8. At all the pHs tested except pH 2.0, no significant changes of GSP secondary structure were observed. GSP exhibited beneficial functional properties such as preferable solubility and emulsifying activity, while the foaming properties and water holding capacity were relatively poor compared to SPI. It could then be employed to soup, sauce, beverage or meat product for improving nutritional and sensory quality of these foods at appropriate pHs.     

Chemical constituents with antioxidant activities from litchi (Litchi chinensis Sonn.) seeds

Litchi (Litchi chinensis Sonn.) is widely accepted as a delicious fruit in China and its seeds have been commonly used in traditional Chinese medicine to relieve neuralgic pain. In the present study, chemical investigation of the 95% ethanol extract of Litchi chinensis seeds led to the isolation of four new compounds, 2α,3α-epoxy-5,7,3′,4′-tetrahydroxyflavan-(4β-8-catechin) (5), 2β,3β-epoxy-5,7,3′,4′-tetrahydroxyflavan-(4α-8-epicatechin) (7), litchiol A (9) and litchiol B (12), together with 11 known ones, 2,5-dihydroxy-hexanoic acid (1), soscopoletin (2), coumaric acid (3), protocatechuic acid (4), 2α,3α-epoxy-5,7,3′,4′-tetrahydroxyflavan-(4β−8)-epicatechin (6), pterodontriol d-6-O-β-d-glucopyranoside (8), Narirutin (10), naringin (11), dihydrocharcone-4′-O-β-d-glucopyranoside (13), pinocembrin-7-rutinoside (14), pinocembrin-7-neohesperidoside (15). Their structures were mainly elucidated on the basis of NMR, MS, IR, CD and UV spectral evidences. Antioxidant activities of 14 compounds were determined by DPPH radical-scavenging assay and Trolox equivalent antioxidant capacity assay, and the results showed that four compounds, protocatechuic acid (4), 2α,3α-epoxy-5,7,3′,4′-tetrahydroxyflavan-(4β-8-catechin (5), 2α,3α-epoxy-5,7,3′,4′-tetrahydroxyflavan-(4β−8)-epicatechin (6), 2β,3β-epoxy-5,7,3′,4′-tetrahydroxyflavan-(4α-8)-epicatechin (7), exhibited moderate antioxidant activities.     

Physicochemical and structural characterization of Lima Bean (Phaseolus lunatus) globulins

A globulin fraction from Phaseolus lunatus have been isolated and characterized. The fractionation scheme used allowed to obtain a Globulin partially purificated. Globulin purification by ultracentrifugation allowed to isolate three peaks with different sedimentation coefficient, while gel filtration chromatography yielded two species, I and II, which were later identified as 11S and 7S globulins, respectively. Species II, 7S globulin from P. lunatus, seems to have a molecular mass of 72 kDa and to be constituted by polypeptides of 34-36, 25-27 and 16-18 kDa without intermolecular disulfide bonds. These polypeptides would present certain heterogeneity, as suggested by the results of isoelectric focusing and electrophoresis analyses. This protein exhibited some particular features, including a lower molecular mass and higher thermal stability than typical vicilins. Species I, with a molecular mass of 336 kDa, would be constituted by subunits of 53-55 and 40-41 kDa formed by smaller polypeptides (around 30 and 20 kDa) linked by disulfide bonds. These features, together with the existence of basic and acid polypeptides in the molecule, would confirm that species I is a globulin of the legumins, 11S globulins or α-conglutin family.     

Physicochemical and functional properties of whole legume flour

The physicochemical, functional and pasting properties of whole flours from pinto bean, lima bean, red kidney bean, black bean, navy bean, small red bean, black eye bean, mung bean, lentil and chickpea were investigated. Significant differences in physicochemical characteristics and functional properties were observed (P < 0.05). Bulk densities, water absorption indices, water solubility indices, oil absorption capacities, emulsion activities, and emulsion stabilities ranged from 0.543 g/mL to 0.816 g/mL, 4.09 g/g to 6.13 g/g, 19.44 g/100 g to 29.14 g/100 g, 0.93 g/g to 1.38 g/g, 61.14%–92.20%, and 84.15%–96.90%, respectively. Phaseolus legume flour exhibited higher water absorption capacity, oil absorption capacity, emulsion activity, and emulsion stability compared with other kinds of legume flour. Pasting properties were significantly different (P < 0.05). Pasting temperatures and the peak, final, and setback viscosities of the flours ranged from 73.2 °C to 83.0 °C, 96.2 RVU to 216.8 RVU, 118.5 RVU to 243.8 RVU, and 28.3 RVU to 103.2 RVU, respectively.     

Physical properties,chemical characterization and fatty acid composition of Mexican chia (Salvia hispanica L.) seeds

Chia seeds were utilized by Aztecs as food and for medicinal purposes. Nowadays, this crop is gaining importance in many countries, due to its nutritional attributes. Some physical properties and chemical characteristics of chia seeds from four different regions of Mexico were evaluated and compared. Seed size distribution was not significantly affected (P > 0.05) by the region, with similar values of seed length (2.03–2.10 mm), width (1.27–1.32 mm), thickness (0.77–0.81 mm) and surface area (4.95–5.42 mm²). Bulk density (662–741 kg m^?3), geometry and granulometric distribution were also determined. Origin of tested seeds significantly (P < 0.05) influenced their composition; all seeds had high contents of protein (18.5–22.3%), fat (21.5–32.7%) and fibre (20.1–36.1%). Chia seeds ratio between omega‐3 and omega‐6 fatty acids was 3:1 for the studied regions; seeds from Chiapas and Michoacán had the highest proportion of ω‐6 and ω‐3 fatty acids. The studied seeds contained phenolic compounds in the range of 0.53–0.71 mg GAE g^?1.     

Sequential extraction of polysaccharides from enzymatically hydrolyzed okara byproduct: Physicochemical properties and in vitro fermentability

Okara, a byproduct of soymilk production, has been upgraded through the use of an enzymatic treatment with Ultraflo L® to give a product (okara^ET) which has a higher content of soluble dietary fibre and an enhanced ratio of soluble: insoluble fibre than is found in okara without treatment. Polysaccharides were isolated from okara^ET by sequential extraction to yield soluble fractions in water (22%), CDTA (8.7%), alkali (37.7%) without and NaClO₂ (9.1%) and the cellulosic residue represents a (22.5%). The physicochemical properties of okara^ET were improved due to the enzymatic treatment: oil retention capacity (6.94 g/g), water retention capacity (10.76 g/g) and swelling capacity (13.85 g/g) were higher than in okara that had not undergone enzymatic treatment. The gelation capacity (8%) and the cation exchange capacity (8.96 mEq/kg) of okara^ET were lower than that of other byproducts. Short chain fatty acid production during in vitro fermentation of okara^ET by a pure culture of Bifidobacterium bifidus was mainly represented by acetic acid, followed by propionic and butyric acids. In addition, the decreases in pH and substrate consumption demonstrated the bifidogenic capacity of okara^ET.     

Physicochemical and structural characterisation of globulin and albumin from common buckwheat (Fagopyrum esculentum Moench) seeds

The physicochemical and conformational properties of globulin (BG) and albumin (BA) fractions from common buckwheat seeds were characterised, and compared with those of buckwheat protein isolate (BPI). The polyphenol contents were also evaluated. The polyphenol content in BA was much higher than that in BG, and most of the polyphenols in the BA was in the free form, whilst that in the BG and BPI was mainly in the protein-bound form. The BA had higher content of uncharged polar amino acids, but lower acidic amino acids than BG. The protein solubility-pH profile of the BG and BA were very different, especially at pH 4.0–6.0. Far-UV and near-UV CD and intrinsic fluorescence spectra indicated that the secondary and/or tertiary conformations of BA were much more flexible than those of BG, but also more easily affected by the polyphenols. The results indicated that the properties of BG and BA varied considerably, and were largely dependent upon their polyphenol levels and the interactions of the polyphenols and the proteins.     

Physicochemical properties and radical scavenging capacities of pepsin-solubilized collagen from sea cucumber Stichopus japonicus

Pepsin-solubilized collagen (PSC) was successfully prepared from the body wall of sea cucumber Stichopus japonicus. Ultraviolet–visible and Fourier transform infrared spectroscopic analyses showed that the PSC was a high-purity collagen that maintained the intact triple-stranded helices. Physical and chemical characterization of the PSC showed a isoelectric point of 4.14, a superior moisture-absorption and retention capacities comparing to glycerol, a minimum solubility at pH 5.0 in 0.5 M acetic acid, and a sharp decrease in solubility in the presence of low concentration of NaCl. The viscosity of PSC was shown to decrease continuously as the temperature was increased. The radical scavenging activity of the PSC was characterized with two model systems: for hydroxyl radicals, the PSC was more active than vitamin C but less active than sulfourea; for 1,1-diphenyl-2-picrylhydrazyl radicals, the PSC was more active than vitamin E.     

Antioxidative and functional properties of protein hydrolysate from defatted skipjack (Katsuwonous pelamis) roe

Antioxidative and functional properties of protein hydrolysate from defatted skipjack (Katsuwonous pelamis) roe, hydrolysed by Alcalase 2.4 L (RPH) with different degrees of hydrolysis (DH) at various concentrations were examined. As DH increased, the reduction of DPPH, ABTS radicals scavenging activities and reducing power were noticeable (p < 0.05). The increases in metal chelating activity and superoxide scavenging activity were attained with increasing DH (p < 0.05). However, chelating activity gradually decreased at DH above 30%. All activities except superoxide anion radical scavenging activity increased as the concentration of hydrolysate increased (p < 0.05). Hydrolysis using Alcalase could increase protein solubility to above 80% over a wide pH range (2–10). The highest emulsion ability index (EAI) and foam stability (FS) of hydrolysates were observed at low DH (5%) (p < 0.05). Concentrations of hydrolysates determined interfacial properties differently, depending on DH. The molecular weight distribution of RPH with 5%DH (RPH5) was determined using Sephadex G-75 column. Two major peaks with the molecular weight of 57.8 and 5.5 kDa were obtained. Fraction with MW of 5.5 had the strongest metal chelating activity and ABTS radical scavenging activity. The results reveal that protein hydrolysates from defatted skipjack roe could be used as food additives possessing both antioxidant activity and functional properties.     

Comparative study of the functional,thermal and pasting properties of flours from different field pea (Pisum sativum L.) and pigeon pea (Cajanus cajan L.) cultivars

Physicochemical, functional, thermal and pasting properties of flours from field pea (LFP-48 and PG-3) and pigeon pea (AL-15 and AL-201) cultivars were determined and related to each other using Pearson correlation and principal component analysis (PCA). Field pea flours (FPF) were significantly (P < 0.05) different from pigeon pea flours (PPF) in their lower ash and higher fat and protein contents. FPF also exhibited higher L^∗, ΔE value, water solubility index (WSI), oil absorption capacity (OAC), foaming capacity (FC) and lower a^∗, b^∗ value, water absorption index (WAI) and water absorption capacity (WAC) in comparison to PPF. FPF differed significantly from PPF in exhibiting lower transition temperatures (T_o, T_p, T_c), enthalpy of gelatinization (ΔH_gel), peak height index (PHI) and higher gelatinization temperature range (R). PCA showed that LFP-48 and PG-3 flours were located at the far left of the score plot with a large negative score, while the AL-15 and AL-201 flours had large positive scores in the first principal component. Several significant correlations between functional, thermal and pasting properties were revealed, both by Pearson correlation and PCA. Pasting properties of the flours, measured using the rapid visco analyzer (RVA), also differed significantly. PPF were observed to have higher pasting temperature (PT), peak viscosity (PV), trough viscosity (TV), breakdown (BV), final viscosity (FV) and lower setback viscosity (SV) as compared to FPF.     

Physicochemical, in vitro digestibility and functional properties of carboxymethyl rice starch cross-linked with epichlorohydrin

Cross-linked carboxymethyl rice starches (CL-CMRSs) were prepared from reactions between native rice starch and varied concentrations (0.1–15% w/w, M-0.1 to M-15) of epichlorohydrin (ECH) in a simultaneous carboxymethylation-crosslinking reaction setup using methanol as the solvent. The degree of carboxymethyl substitution was between 0.24 and 0.28, while apparent amylose contents were lowered due to modification. SEM images showed minor change on the granule surface, while XRD profiles indicated slight loss of crystallinity. DSC thermograms revealed no transition peak in all treated samples. The water uptake (WU), swelling volume (SV) and free swelling capacity (FSC) of CL-CMRSs increased significantly as a result of the modification, while swelling of CMRSs cross-linked with 2% (M-2) and 3% (M-3) ECH yielded FSC values and WU values that were much greater than those of native starches and were comparable to that of Explotab®. All modified starch samples showed increased amount of rapidly digestible starch (RDS), while cross-linking with 5–7.5% ECH raised the resistant starch (RS) content, compared to native starch. M-2 also showed promising results in tablet disintegration test. ECH–CL–CMRSs could potentially be used as an excipient in pharmaceutical and food/food supplement products.     

Chemical composition and functional properties of Ulva lactuca seaweed collected in Tunisia

The chemical composition and some functional properties of the dried “Ulva lactuca” algae, collected from the littoral between the Taboulba and Sayada area, were determined. The dried “U. lactuca” algae were investigated for their soluble, insoluble and total dietary fibre content, mineral amount, amino acid and fatty acid profiles, swelling capacity (SWC), water holding capacity (WHC) and oil holding capacity (OHC). Results showed that “U. lactuca” alga powder was characterised by a high content of fibres (54.0%), minerals (19.6%), proteins (8.5%) and lipids (7.9%). The neutral fibres contain hemicellulose (20.6%), cellulose (9.0%) and lignin (1.7%). The proteinic fraction analysis indicated the presence of essential amino acids, which represent 42.0% of the total amino acids. The fatty acids profile was dominated by the palmitic acid, which represents about 60.0% of the total fatty acids, followed by oleic acid (16.0%). The study of the functional properties proved that SWC, WHC and OHC of this alga varied with temperatures and that were comparable to those of some commercial fibre rich products.