Effects of pH and salt concentration on functional properties of rambutan (Nephelium lappaceum L.) seed albumin concentrate

Searching new protein sources is essential due to an increase in protein demand. In this study, rambutan seed albumin concentrate (RSAC) with the protein content of 80.8% was isolated from defatted rambutan seed meal. The effects of pH and sodium chloride concentration on solubility and functional properties of RSAC were investigated. RSAC had minimum solubility at pH 4. Water absorption capacity at pH 7 and oil absorption capacity of RSAC were 0.79 and 6.13 mL g^?1, respectively. Both foaming and emulsifying capacities achieved maximal levels at pH 12. In sodium chloride solution, foaming capacity and stability achieved maximal levels at the concentration of 0.6 mol L^?1, while the highest emulsifying capacity and stability were noted at the concentration of 0.2 mol L^?1. The least gelation concentration of RSAC was 100 g L^?1 and this value decreased by five times as salt concentration in the protein solution was 0.6 mol L^?1. RSAC was a potential functional ingredient in food processing.     

Response surface optimization and characteristics of rambutan (Nephelium lappaceum L.) kernel fat by hexane extraction

Response surface methodology (RSM) was used to study the effect of moisture content (1.59-18.41 g/100 g), extraction time (2.3-10.7 h) and particle size (0.09-2.11 mm) on the fat yield from rambutan kernels using hexane extraction. The physical and chemical characteristics of rambutan fat were also determined. The optimum conditions obtained from response surface analysis was 4.99 g/100 g moisture, 1.05 mm particle size and 9.2 h extraction time. Under these optimum conditions, the maximum fat yield was 37.35 g/100 g. The extracted fat was a white solid at room temperature. The physical and chemical characteristics of the extracted fat compared well with those of conventional fats. The high level of arachidic acid (∼ 34.3 g/100 g fat) and low iodine value in rambutan kernel fat permits the use of the fat, especially where oxidation may be a concern, without its being subjected to hydrogenation.     

红毛丹果皮色素及其稳定性的研究

红毛丹(Nephelium lappaceum L.)果皮含有较高的色素。为综合利用植物色素资源,对红毛丹果皮色素进行提取与纯化,并从光照、温度、pH 值、氧化与还原介质、防腐剂、酸味剂、糖类、VC 和金属离子方面对该色素的稳定性进行研究。结果表明：红毛丹色素属花色苷类;对自然光、高温、H2O2 和Na2SO3 的耐受性较差,在pH3 以下色泽较稳定;低浓度防腐剂苯甲酸钠对色素稳定性影响较小,柠檬酸具有一定的增色作用;乳酸、葡萄糖和蔗糖、VC 对色素的稳定性无明显的影响,但Fe3+、Fe2+、Pb2+、Sn2+ 对该色素稳定性起不利的作用。该研究为开发植物新的天然色素产品提供理论参考。     

Development of low‐fat sausages using basil seed gum (Ocimum bacilicum L.) and gelatin as a fat replacer

This research was performed to evaluate the rheological properties of myofibrillar protein gels (MPs) with basil seed gum (BSG) alone or in combination with gelatin (0.25%, 0.5%), and to determine the physicochemical properties of low‐fat sausages (LFSs) manufactured with BSG alone (0.5%) or combined with gelatin (0.25%). Viscosity and cooking yields (%) of MPs with BSG alone or in combination with gelatin were higher than those of the control. However, gel strength of MPs with the combination of BSG and gelatin (0.25%) was higher than that with BSG alone. The combination of BSG and gelatin produced a more stable and denser structure than control or BSG alone. In the LFSs, the addition of BSG reduced the percentages of expressible moisture and cooking loss, and the combination of the BSG and gelatin improved gumminess and cohesiveness compared to BSG alone. The use of BSG as a water binding agent and gelatin to improve gel formation will be considered as fat replacer for the manufacture of low‐fat comminuted sausages.     

Preparation of free, soluble conjugate, and insoluble-bound phenolic compounds from peels of rambutan (Nephelium lappaceum) and evaluation of antioxidant activities in vitro

The soluble phenolic compounds of rambutan peels (RP) were extracted by microwave-assisted extraction (MAE) and the operating parameters were optimized. The optimal conditions obtained were ethanol concentration of 80.85%, extraction time of 58.39 s, and the ratio of liquid to solid of 24.51:1. The soluble phenolic content by MAE was 213.76 mg GAE/g DW. The free, soluble conjugate, and insoluble-boaund phenolic compounds were prepared by alkaline hydrolysis, and the contents of 3 fractions were 185.12, 27.98 and 9.37 mg GAE/g DW, respectively. The contents of syringic acid and p-coumaric acid were high in the free fraction, showing 16.86 and 19.44 mg/g DW, and the soluble conjugate and insoluble-bound phenolics were mainly composed of gallic acid and caffeic acid. Furthermore, the antioxidant activities of 3 fractions were evaluated in 5 model systems. Results indicated that the free fraction had high antioxidant activities, compared with the soluble conjugate and insoluble-bound fractions.     

Determination of antibacterial effects and total phenolic contents of grape (Vitis vinifera L.) seed extracts

In the study, antibacterial activities of the seed extracts of three different grapes were examined against fifteen bacteria, and total phenolic contents of the extracts were additionally determined. The contents of total phenolic compounds of the grape seed extracts were 589.09 (Hasandede), 506.60 (Emir) and 549.54 (Kalecik Karasi) mg gallic acid equivalent (GAE) per gram with acetone:water:acetic acid (90:9.5:0.5). These extracts at 1%, 2.5%, 5% and 10% concentrations were tested for their antibacterial effects by using the agar diffusion method against some pathogenic and spoilage bacteria including Aeromonas hydrophila, Bacillus cereus, Enterobacter aerogenes, Enterococcus faecalis, Escherichia coli, E. coli O157:H7, Klebsiella pneumoniae, Mycobacterium smegmatis, Proteus vulgaris, Pseudomonas aeruginosa, Pseudomonas fluorescens, Salmonella enteritidis, Salmonella typhimurium, Staphylococcus aureus and Yersinia enterocolitica. All tested bacteria were inhibited by the grape seed extracts using agar well diffusion method. The most sensitive of the bacteria was A. hydrophila while Hasandede grape seed extract was the most inhibitive extract on test bacteria. Hasandede seed extract at 10% concentration gave the largest inhibition zone diameter (30.67 mm) against A. hydrophila. According to serial dilution method, while all the grape seed extracts at 0.5% and 1% concentrations had generally bacteriostatic activities against E. coli O157:H7, the same extracts appeared to have bactericidal effects at concentrations above 2.5%. In addition, the extracts at all concentrations had bactericidal activities against S. aureus at the end of 48 h. and A. hydrophila at the end of 1 h.     

Evaluation of cooking time and quality of seven diverse cowpea (Vigna unguiculata (L.) Walp.) varieties

Seven cowpea ( Vigna unguiculata (L.) Walp.) varieties, which were part of a larger collection evaluated in agronomic field trials in Botswana, were selected for characterization of cooking time and quality. Newly harvested seed was kept in the open air for 2 weeks, then stored at 4°C and 40% relative humidity for 3 months. Duplicate samples were tested for cooking time with and without 12-h prior soaking. Varieties showed differences ( P < 0.01) in cooking time and response to soaking, although the overall effect of soaking was insignificant. Cooking times ranged from 29 to 64 min without soaking and 36 to 56 min after soaking, with small-seeded varieties having the longer cooking times. The seed coat of some varieties readily became soft, but others remained tough or split before finally softening.     

Lipophilic compounds and thermal behaviour of African mango (Irvingia gabonensis (Aubry-Lecomte ex. O'Rorke) Baill.) kernel fat

Irvingia gabonensis kernels are a promising oleiferous source. Their total lipid content was 72.3%. C14:0 and C12:0 represented the most abundant fatty acids. Triacylglycerols with ECN 32 and 46–48 were identified for the first time by HPLC-DAD-ESI-MSⁿ. Comprehensive GC-FID and GC-MS analyses revealed novel insights into minor lipids like phytosterols and tocochromanols. Among the latter, γ-tocopherol was found to be the major vitamer. β-Sitosterol and stigmasterol were the prevailing phytosterols in the kernel fat. The high saturation level of the fat resulted in a sharp differential scanning calorimetry melting curve with a high melting temperature of 42.1 °C. The fat remained solid over a wide temperature range and still contained 66.6% solid fats at 35 °C. Consequently, kernels of the African mango provide a viable source for the recovery of solid fats applicable in the food industry as sustainable alternatives to replace palm-based fats or hardened vegetable oils.     

Isoelectric focusing and sodium dodecylsulphate electrophoresis of buffer soluble seed proteins of twelve varieties of winged bean (Psophocarpus tetragonolobus L.)

Buffer-soluble seed proteins of 12 varieties of winged bean (Psophocarpus tetragonolobus L.) were separated by ultrathin-layer isoelectric focusing (IEF) and sodium dodecylsulphate electrophoresis(SDS-PAGE). Whereas the molecular weight spectra of the proteins obtained by SDS-PAGE were identical for all varieties studied, the IEF patterns showed variety specificity for each sample. Most of the variety specific protein bands were identified as glycoproteins. The zymograms of the isoelectically focused trypsin inhibitors were variety specific in both activity and isoelectric point distribution.     

Composition,variation of nutritional contents in leaves,seed protein,fat and fatty acid profile ofchenopodium species

The foliage of Chenopodium belonging to 10 species were analysed for selected nutritional and antinutritional components. The overall range of moisture was 757-910 g kg^?1, carotenoid 78-190 mg kg^?1, vitamin C 0.5-2.4 g kg^?1, protein 26-64 g kg^?1, nitrate 2.6-5.0 g kg^?1 and oxalate 9-39 g kg^?1 (fresh wt). Variation of all the six parameters with respect to leaf position from the apex showed the highest amount of carotenoid at 7-8, vitamin C at 9-10, protein at 5-6 and nitrate in the youngest leaves, followed by a continuous decrease with age (increasing position). However, oxalate contents always tended to increase with leaf position (age). The protein, fat and fatty acid composition in seeds of eight species were also analysed. Protein varied from 106 to 142 g kg^?1 and fat from 30 to 62 g kg^?1; palmitic, oleic and linoleic were the major fatty acids in the oils.     

Lipase-catalyzed production of solid fat stock from fractionated rice bran oil,palm stearin,and conjugated linoleic acid by response surface methodology

Solid fat stock was produced from the fractionated rice bran oil (solid phase, S-RBO) and palm stearin (PS) through lipase-catalyzed reaction, in which conjugated linoleic acid (CLA) was intentionally incorporated. For optimizing the reaction, response surface methodology (RSM) was employed with four reaction variables such as water activity, reaction temperature, reaction time, and mole ratio of S-RBO to PS. The predictive model was adequate due to no significant lack of fit and satisfactory level of coefficient of determination (R² = 0.95). The melting point of solid fat stock was affected by reaction time and substrate mole ratio, whereas water activity and reaction temperature had no significant effect. Based on ridge analysis, the combination of A_w (X₁; 0.32), reaction temperature (X₂; 65.3 °C), reaction time (X₃; 28.9 h), and substrate mole ratio (X₄; 1:1.1) was optimized for producing solid fat stock with target melting point of 43.8 °C. The solid fat stock (SFS) contained 39.9% palmitic, 31.3% oleic, 13.2% linoleic acid, and 10.9% CLA isomers. Solid fat contents were 23.4, 10.9, and 2.5% at 20, 30, and 40 °C, respectively. These results suggested that RSM can be used to optimize the lipase-catalyzed production of a solid fat stock.     

Impact of household food processing strategies on antinutrient (phytate,tannin and polyphenol) contents of chickpeas (Cicer arietinum L.) and beans (Phaseolus vulgaris L.): a review

Pulses, which include beans and chickpeas, are major constituents of the human diet. They are important sources of energy and nutrients, particularly protein, folate and minerals. However, they also contain antinutrients which bind minerals, mainly iron and zinc, rendering them less bioavailable or unavailable for absorption. The levels of these antinutrients may be reduced by food processing techniques such as soaking and germination. Researchers have used these techniques in a number of studies; however, there is no consensus regarding the optimum processing conditions for reduction in the levels of these antinutrients. Thus, this review was conducted to describe the results of studies on soaking and germination of chickpeas and beans. A systematic search was carried out utilising Food Science and Technology Abstracts (FSTA) (1969 to present), Web of Science (1899 to present) and Scopus (1823 to present). A total of thirty‐three articles were reviewed. Both soaking and germination resulted in significant but variable degrees of reduction in levels of antinutrients in most studies.     

美藤果品质及其影响因素分析

美藤果作为一种高营养价值的新型油料，具有重要的开发价值。检测了中国西双版纳、普洱、红河及老挝102份美藤果的品质指标，并考察了产地、病虫害与施肥对美藤果品质的影响。结果表明：美藤果平均含油量为37.4%，平均蛋白质含量为22.1%，油中不饱和脂肪酸含量高达92.17%，其中亚麻酸占45.34%。产地对美藤果品质具有显著影响，而施肥、病虫害对美藤果品质影响较小。不同产地美藤果的蛋白质、硬脂酸、亚麻酸含量具有显著差异，其中西双版纳样品的蛋白质含量显著高于普洱的，中国西双版纳、红河与老挝样品的硬脂酸含量均显著高于中国普洱的，而中国普洱样品的亚麻酸含量显著高于老挝和中国红河的。此外，施肥有利于提高美藤果的含油量。     

Comparison of isoflavones composition in seed,embryo, cotyledon and seed coat of cooked-with-rice and vegetable soybean (Glycine max L.) varieties

In order to study the content and composition of isoflavones retained in soybean seed component, obtained each component part the embryo, cotyledon and seed coat tissues of nine different soybean varieties were analyzed for 12 isoflavones using high performance liquid chromatography with photo diode array detector (HPLC-PDA) and were compared to each other. A total average concentration of isoflavone was 2887 μg g⁻¹ in embryo, 575 μg g⁻¹ in whole seed, 325 μg g⁻¹ in cotyledon, and 33 μg g⁻¹ in seed coat. With respect to each tissue of soybean varieties, isoflavone content was highest in Geomjeongkong 2 embryo (5701 μg g⁻¹), Geomjeongolkong whole seed (1321 μg g⁻¹), Heugcheongkong cotyledon (951 μg g⁻¹), and Keunolkong seed coat (56 μg g⁻¹). Isoflavone was least present in Keunolkong embryo (341 μg g⁻¹), Hwaeomputkong whole seed (175 μg g⁻¹), Seonheukkong cotyledon (81 μg g⁻¹), and Seoklyangputkong seed coat (5 μg g⁻¹). Overall, embryo and seed coat of all nine varieties contained isoflavones at the highest and lowest level, respectively. Isoflavones accumulated in the order of malonylglycoside, glycoside, acetylglycoside, and aglycon, among which malonylglycoside was the most abundant form ranging from 66% to 79% of the total isoflavone content in all three tissues. The embryo of cooked-with-rice soybean with black seed coat appears to be the best source of isoflavone.     

Fatty acid profile of muscles,liver and mesenteric fat in wild and reared perch (Perca fluviatilis L.)

This study addressed determinations of the fatty acid profile of muscle, liver and mesenteric fat in European perch originating from natural aquifers and from intensive rearing in a closed circuit on an artificial feed mixture. The qualitative composition of fatty acids was identical in both groups of perch, except for 16:4 acid identified exclusively in the reared perch. The study demonstrated equal concentrations of saturated (SFA) and unsaturated (UFA) fatty acids in muscles, liver and mesenteric fat of both groups of perch. The wild fish, however, were characterised by lower concentrations of monoenoic (MUFA) and higher concentrations of polyenoic (PUFA) fatty acids. Analyses also demonstrated similar contents of n − 3 PUFA in muscles and their diversified concentrations in liver and mesenteric fat (higher in the wild fish), as well as a higher content of n − 6 PUFA in all samples. The lower content of MUFA in the wild perch was mainly due to lower concentrations of cis18:1 n − 9 and 20:1 n − 9, whereas the higher content of n − 3 PUFA was due to a higher concentration of DHA, and the higher content of n − 6 PUFA was due to a higher concentration of arachidonic acid (AA). The biggest differences between wild and reared perch were detected for AA. The wild and reared perch were also found to differ in the n − 3/n − 6 ratio (higher in the reared fish) and to have similar values for atherogenic index (AI) (except for liver and mesenteric fat) and thrombogenicity index (TI).     

Antioxidant activity,phenolic and anthocyanin contents of various rhubarb (Rheum spp.) varieties

Antioxidant activity (ABTS assay), total phenolics and total anthocyanins were determined in the petioles of twenty‐nine rhubarb (Rheum spp.) varieties. Antioxidant activity ranged from 463 ± 50 (Rheum officinale) to 1242 ± 2 μmol Trolox per g DW (Valentine). The phenolic content varied from 673 ± 41 (Loher Blut) to 4173 ± 23 mg GAE/100 g DW (Plum Hutt) and had a low correlation (r = 0.663) with antioxidant results. Seven of the varieties (Plum Hutt, Valentine, Minnesota No. 8, Cherry Red, Cawood Delight, Coulter McDonald and OR 23) had higher total phenolics than kale, a vegetable rich in phenolics. The concentration of anthocyanins ranged from 19.8 ± 1.5 (Crimson Red) to 341.1 ± 41.6 mg/100 g DW (Valentine). The percentages of two main anthocyanins in rhubarb, cyanidin 3‐glucoside and cyanidin 3‐rutinoside varied from 66.07:33.93, respectively, in Valentine to 9.36:90.64, respectively, in R. officinale.     

Phenolic content and antioxidant activity of four date palm (Phoenix dactylifera L.) fruit varieties grown in Tunisia

Fruits of date palm ( Phoenix dactylifera L.) are consumed throughout the world and are a vital component of the diet in most Arabian countries. This study has been carried out to evaluate the total phenolic content and the antioxidant activity of four date palm fruit varieties grown in Tunisia. All measurements were made at the 'tamar' stage-the final stage of fruit ripeness. The date varieties were found to be rich in total phenolic ranging from 209.42 mg of equivalent gallic acid/100 g fresh weight in Kentichi to 447.73 mg equivalent gallic acid/100 g fresh weight in Allig. The date varieties studied were characterised by a high antioxidant activity ranging from 866.82 for the Deglet Nour to 1148.11 μmol Equivalent Trolox/100 g fresh weight for Khouet Kenta by the ABTS method. In fact, the DPPH method revealed that Allig having the lowest antioxidant activity (0.72) followed by Deglet Nour (1.53), Kentichi (1.68) and Khouet Kenta variety (1.96). This study suggest that Tunisian date palm fruit may serve as a good source of natural antioxidants and could potentially be considered as a functional food ingredient.