Changes in carbohydrates of germinating fenugreek seeds (Trigonella foenum graecum L.)

The effect of germination at 25 °C for 96 h in the dark on the carbohydrates of fenugreek seed was investigated. Reducing, total reducing, non-reducing sugar, and pentosan contents increased. Polysaccharides estimated as starch decreased. Fenugreek contained mucilage (18%), which decreased considerably during germination. The decline in mucilage content was accompanied by a drop in galactan content. Total pectic content did not change, but there was a decline in the high methoxy pectin content, while protopectin, and the low methoxy pectate salts of calcium and magnesium increased. The 70% ethanol soluble carboydrates were chromatographically determined. Fenugreek seeds contained sucrose, raffinose, stachyose, and an unidentified sugar ( I ). A marked increase in sucrose content was observed after germination. Raffinose, stachyose and the unknown sugar ( I ) decreased, while another unknown ( II ) appeared. The two unknown sugars may be members of the raffinose family. Maltose and fructose appeared in measurable amounts after germination.     

Characterisation of germinated fenugreek (Trigonella foenum‐graecum L.) seed fractions

Germinated fenugreek seeds were separated into endosperm, seed coat and sprouts with an overall yield of 78%. Germinated endosperm, sprouts and ungerminated endosperm contained 39.25%, 36.12% and 48.20% protein, respectively. Germinated seed coat had 55.80% insoluble and 86.96% total dietary fibre, whereas ungerminted seed coat had 31.90% and 77.10% respectively. Sprouts were rich in polyphenols (97.55 mg per 100 g). At 200 ppm concentration, the antioxidant activity of the extracts of seed coat, sprouts and endosperm from germinated fenugreek seeds was 79.87%, 49.05%, and 13.42% where as the seed coat and endosperm of ungerminated fenugreek exhibited 90.94% and 10.13% antioxidant activity respectively. The GC analysis of the ester derivatives of the fixed oils of above fractions showed discernable changes in fatty acid profile. Atomic absorption spectroscopy analysis of the above fractions showed overall differences in their mineral content particularly calcium, zinc, copper, iron, potassium, manganese and magnesium.     

Evaluation of debittered and germinated fenugreek (Trigonella foenum graecum L.) seed flour on the chemical characteristics,biological activities,and sensory profile of fortified bread

Germination of fenugreek seed showed better nutraceutical profile as evaluated by in vivo (oral glucose tolerance and acute antihypertriglyceridemic tests) on rats and in vitro DPPH and enzyme inhibition assays (α‐glucosidase, lipase, and lipoxygenase). Attempts were made to develop debittered and germinated fenugreek seed flour (DGFSF) by soaking in acesulfame (0.25%, 8 hr), curd (1:1 in water, 8 hr) and sucrose (5%, 8 hr) solution at 1:4 (wt/vol) ratio for debittering and then germinated, of which curd showed the maximum extent of debittering. The effect of substitution of wheat flour with 5, 10, 15, and 20% (wt/wt) of DGFSF on chemical characteristics and sensory properties was investigated; 10% fortified bread was organoleptically acceptable and had enhanced protein and fiber contents. Fortification increased the bulk density and crumb firmness, decreased the specific loaf volume, and darkened the crumb color. Glycemic index of the bread decreased with 10% DGFSF, which is indicative of desirable health benefits.

Practical applications

Fenugreek seeds are major constituent of Indian spices, bitter to taste and possess various medicinal properties. These seeds are an excellent source of dietary fiber and protein. Although incorporated into traditional foods, its bitterness limits its wide usage. In India, soaking and germination of seeds in water or curd was practiced traditionally since ancient days. Germination and debittering improved antioxidant activity, and various in vitro and in vivo bioactivities. Incorporation of debittered flour improved the polyphenolic, protein, and dietary fiber contents in bread which in turn demonstrated reduced rate of in vitro starch digestibility or lower glycemic index     

Biochemical studies on some non conventional sources of protein Part 3. The molasse

Among the high carbohydrate content the cane molasses contains considerable amount of nitrogen compounds including proteins and amino acids. Protein hydrolyzates showed the presence of 16 amino acids with aspartic and glutamic acids and alanine as the major acids in both states bound and free, and there were two unidentified N-containing free acids. Fe, Zn, Mn and Cu were predominant microminerals, K and P were found to be present and in smaller quantities Na.     

Inhibitors of human and bovine trypsin and chymotrypsin in fenugreek (Trigonella foenum-graecum L.) seeds. Isolation and characterization

Three fenugreek inhibitors (TFI-A8, TFI-N2, and TFI-B2) were isolated from an inhibitor preparation by anion exchange chromatography and subsequent preparative isoelectric focusing using immobilized pH gradients and the canal technique. The purified inhibitors inhibited the enzymes tested differently: TFI-A8 exhibited a high inhibition of trypsin (8.2 mg human trypsin/mg and 8.1 mg bovine trypsin/mg) and a very low inhibition of chymotrypsin (0.8 mg human chymotrypsin/mg and 1.0 mg bovine chymotrypsin/mg). TFI-N2 inhibited the four enzymes to about the same extent (5.0 mg/mg human and 4.1 mg/mg bovine trypsin; 4.9 mg/mg human and 3.7 mg/mg bovine chymotrypsin). TFI-B2 displayed a high inhibition of trypsin (7.5 mg/mg human and 5.1 mg/mg bovine) and a low inhibition of chymotrypsin (1.8 mg/mg human and 1.9 mg/mg bovine). On average, the human enzymes were inhibited better than the bovine ones by the purified inhibitors. The inhibitors contained high amounts of cystine (five or six disulfide bridges per molecule), aspartic acid, threonine, serine and proline, no valine and methionine and two of them also no tryptophan. Their molecular masses were about 6 kDa. Their inclusion into the Bowman-Birk soybean proteinase inhibitor family is discussed.     

Biochemical studies on some non conventional sources of protein Part 2. Cucurbitaceae seeds

Proximate composition of the two varieties of watermelon Chilian and Giza I besides Cucumis melo var. Aegyptiacus showed that the ration of ash, crude fibre, crude protein and ether extract was as follows: (4.99, 3.86, 5.65); (2.56, 3.25, 1.17); (38.1, 39.4, 38.6) and (56.0, 54.2, 51.0) respectively. Protein hydrolysis for all the varieties showed the presence of 17 amino acids and 15 in the free state. The acidic amino acid contents of the previous varieties were high compared with others. Glutamic acid followed by aspartic acid, leucines and arginine were generally high in all varieties. Relating essential amino acids a high tryptophan content and relatively low threonine and methionine content is characteristic. Fe, Mn, Zn and Cu were predominant among the microminerals. Na was found to be present in smaller quantities than K and P. The implication of these findings are discussed.     

Biochemical and nutritional characteristics of non-conventional protein sources

Some nutritional and antinutritional characteristics of Cucumis sativus L and Lagenaria vulgaris (Molina) Standl seeds ere studied. The mature seed kernels contained 312–318 g kg^?1 crude protein, 9–10 g kg^?1 crude fibre, 444–463 g kg^?1 crude fat, 43–45 g kg^?1 ash and 114–142 g kg^?1 carbohydrates. The biological values of cucumber and bottle gourd proteins ere 74.35 and 74.20 respectively. The essential amino acid profile compared ell ith the FAO/HO scoring pattern except for a deficiency of lysine and isoleucine. Lysine as the first limiting amino acid in both the proteins. The leucine:isoleucine and leucine:lysine ratios did not sho imbalance. Trypsin inhibitor, phytate, lectin and tannin levels ere determined in the defatted decorticated cucurbit seed meals. Heat treatment reduced the trypsin inhibitor and lectin activities in all samples to negligible levels. Levels of phytate and tannins ere found to be similar in all samples.     

Biochemical studies on some non conventional sources of protein Part 1. Tomato seeds and peels

Tomato seeds and skin wastes contain considerable amounts of protein (16.6, 5.7%) respectively. After protein hydrolysis from both seeds and peels the presence of 17 amino acids was stated. The amino acid scores (chemical scores) of tomato pomace were calculated using the FAO/WHO provisional amino acid scoring pattern and reasonable biological value was confirmed. The essential amino acid content and biological value of seed proteins are higher than that of skin proteins. Fe, Zn, Cu and Mn in seeds and peels were predominant among the micro-minerals. K and P were found to be present in greater quantities than Na in seeds and peels.     

Biochemical studies of some non-conventional sources of proteins Part 6. Physicochemical properties of apricot kernel proteins and their changes during detoxification

The physico-chemical properties of apricot kernel proteins before and after detoxification treatments with water and ammonium hydroxide were determined. Water treatment shifted the λ_max to 278 nm while ammonium hydroxide has no effect. Fluorescence spectrum showed emission red shift and quenching for both detoxification treatments. Sedimentation velocity pattern of the untreated proteins contained two peaks having S_20,w values of 6.8S and 11.1S. Detoxified kernels showed aggregates of 15.4S and 16.9S due to water and ammonium hydroxide treatment, respectively. Gel filtration pattern consisted of three peaks for all samples, meanwhile ion-exchange chromatography showed an additional peak. HPLC, SDS-PAGE and isoelectric focusing-PAGE proved dissociation of the high molecular weight proteins as well as removal of the low molecular weight protein fractions due to detoxification treatments.     

罗望子胶与常用胶体的复配研究

为探究K⁺对罗望子胶/κ-卡拉胶复合凝胶的特性及机理的影响,本文采用流变学、质构分析、微观结构和红外光谱四种方法,对不同K⁺添加量的复合凝胶的性能和结构进行研究。流变学结果显示,K⁺的添加使凝胶体系的模量升高,柔量和总形变量降低,K⁺添加量增至15 mmol/L时,表观粘度达到最高值2690 Pa·s;质构分析结果显示随K⁺添加量的增大,凝胶体系强度和硬度增大,但弹性和内聚性相对减少;而红外光谱和微观结构证明了K⁺可以促进两种凝胶体系之间的相互作用,使凝胶孔隙趋于致密均匀,在K⁺添加量15 mmol/L时孔径间壁最为规则结实。结果表明,K⁺的添加能够使凝胶体系表现较好的粘弹性和抗变形性,使网状结构更加紧密,为罗望子胶和κ-卡拉胶的复配应用提供了理论参考。     

Biochemical studies of some non-conventional sources of proteins Part 7. Effect of detoxification treatments on the nutritional quality of apricot kernels

Detoxification of apricot kernels by soaking in distilled water and ammonium hydroxide for 30 h at 47 °C decreased the total protein, non-protein nitrogen, total ash, glucose, sucrose, minerals, non-essential amino acids, polar amino acids, acidic amino acids, aromatic amino acids, antinutritional factors, hydrocyanic acid, tannins and phytic acid. On the other hand, removal of toxic and bitter compounds from apricot kernels increased the relative content of crude fibre, starch, total essential amino acids. Higher in-vitro protein digestibility and biological value was also observed. Generally, the detoxified apricot kernels were nutritionally well balanced. Utilization and incorporation of detoxified apricot kernel flours in food products is completely safe from the toxicity point of view.     

Proteolytic activity,amino acid composition and protein quality of germinating fenugreek seeds (Trigonella foenum graecum L.)

This study determined the changes in proteolytic activity and trypsin inhibitor, due to germination for 120 h, and their relationships to amino acid content and protein quality. The activities of cas-ase, Hb-ase, and BAPA-ase, as well as the trypsin inhibitor of the fenugreek, increased as germination proceeded. Glutamic and aspartic acids were the richest amino acids in fenugreek seeds, followed by leucine, arginine, lysine and proline. After germination, the contents of aspartic acid, phenylalanine, tyrosine, threonine, tryptophan and valine increased, while those of glutamic acid, proline and four of the essential amino acids decreased. All the free amino acids increased after germination, while glycine decreased. Cystine, tryptophan and proline originated in a free form after germination. The chemical score, based on the essential amino acid pattern of whole egg protein, for fenugreek seeds, showed a marked decrease (21%) after germination. The in vitro pepsin, followed by pancreatin digestion, showed a slight increase for the germinated seeds. Germination of seeds lowered the C-PER, a result which indicates that the protein quality decreased.     

Inhibitors of human and bovine trypsin and chymotrypsin in fenugreek (Trigonella foenum-graecum L.) seeds. Demonstration and purification

Fenugreek contained proteinase inhibitors inhibiting 5-9 mg human trypsin, 5-7 mg bovine trypsin, 2-6 mg human chymotrypsin, and 1-3 mg bovine chymotrypsin per g seed material. About 30 inhibitors were electrophoretically detected, and 23 of them, inhibiting all the four enzymes, were characterized by means of their isoelectric points: a group of acid inhibitors (TFI-A1 to A10, pI 4.48-5.12), a group of neutral inhibitors (TFI-N1 to -N6, pI 5.91-6.71), and a group of basic inhibitors (TFI-B1 to -B7, pI 7.76-9.77). To eliminate the galactomannans which complicate further purification, coarsely ground seeds were separated by density into two fractions, seed coats + endosperm and cotyledons + embryos (C + E). Isolation of the fenugreek inhibitors by extraction of fraction C + E, followed by ammonium sulfate fractionation and affinity chromatography on anhydrotrypsin-Sepharose, resulted in an about 700-fold enrichment.     

Biochemical studies of some non conventional sources of protein. Part 4. The proteins of mango waste stone kernels

The gross chemical composition, protein content and amino acid composition of mango stone kernels of four Egyptian varieties (Ewsi, Hendi, Fonso and Timour) were investigated. Carbohydrates are the main components of the seed. The protein content varies between 5.0 and 7.2% and the ether extract ranged from 10.8% to 13.6%. High glutamic acid, aspartic acid and leucine content and low concentration of sulfur-containing amino acids are characteristic for the proteins of mango kernels. Lysine level is also low, the concentration of other essential amino acids is acceptable. Sulfur-containing amino acids are the first limiting ones followed by lysine and threonine.     

Inhibitors of human and bovine trypsin and chymotrypsin in fenugreek (Trigonella foenum-graecum L.) seeds. Reactive sites and C-terminal sequences

The reactive sites and the C-terminal sequences of three trypsin chymotrypsin inhibitors from fenugreek seeds (TFI-B2, TFI-N2, and TFI-A8) were determined by chemical modification and carboxypeptidase degradation of native und enzymatically modified inhibitors. TFI-B2 contained lysine and leucine in the trypsin- and chymotrypsin-reactive sites, respectively, and -(Lys)-Phe-Leu-Ile was the C-terminal sequence. TFI-N2 possessed arginine and leucine in the trypsin- and chymotrypsin-reactive sites, respectively, and -(Tyr)-Lys-Ile-Leu at the C-terminus. TFI-A8 contained two arginines, one in each of the two reactive sites. At least one of these sites, although mainly directed against trypsin, could also bind some chymotrypsin. -(Leu)-Phe-Ile-Arg was found to be the C-terminus in TFI-A8. These results confirmed that all three fenugreek inhibitors belong to the Bowman-Birk proteinase inhibitor family.