Chemical studies on the unripe and ripe fruits of Dennettia tripatela (pepper fruit)

The proximate composition, as well as some mineral, vitamin and anti-nutritional constituents in unripe and ripe fruits of Dennettia tripatela have been investigated. Moisture in the flesh of the fruit varied narrowly, ranging between 81% in the unripe and 82% in the ripe. The unripe and ripe seeds had about 25% and 71% lower moisture contents when compared with the unripe and ripe flesh, respectively. The crude protein and lipid contents in the unripe flesh were 4% DM and 2% DM, respectively; however, the corresponding values in the unripe seed represented 275% and 200% increases. Protein, lipid, fibre and ascorbic acid contents were generally higher in both the flesh and seed of ripe fruits. Tannin and oxalate contents in the flesh of ripe fruits represented about 100% and 50% increases, respectively, over corresponding values in the unripe fruit. The hydrocyanic acid contents tended to decrease from the flesh to the seeds and also from the unripe to the ripe fruits. The values for mineral contents varied widely, but calcium, magnesium and iron were present in appreciable quantities.     

Effect of Maturity Stages and Drying Methods on the Retention of Selected Nutrients and Phytochemicals in Bitter Melon (Momordica charantia) Leaf

ABSTRACT:  The purpose of this study was to investigate the nutrient and phytochemical composition of bitter melon leaves under varying maturity levels and drying techniques. Fresh, oven-dried, and freeze-dried leaves were evaluated over 3 maturity stages. In fresh leaves at various stages, crude fat, crude protein, and soluble dietary fiber contents ranged from 4.2% to 13.6%, 6.4% to 23.1%, and 0.04% to 3.50% on dry-weight basis, respectively. The contents of K, Ca, Mg, Fe, and Zn ranged from 1850.8 to 2811.8, 837.4 to 4978.2, 317.3 to 512.4, 8.4 to 16.7, and 4.1 to 5.9 mg/100 g dry-weight basis, respectively. Vitamin C, β-carotene, and lutein contents ranged from 397.4 to 1275.1, 154.2 to 422.8, and 737.6 to 1304.6 μg/g dry-weight basis. The major flavonoids and phenolic acids were rutin, gentistic acid, and  o -coumaric acid, which ranged from 7.57 to 12.75, 2.53 to 10.11, and 4.24 to 9.75 mg/g dry-weight basis, respectively. In oven-dried samples, 40.2% to 52.3% of vitamin C, 35.4% to 55.4% of β-carotene, 25.6% to 71.6% of lutein, 26.4% to 84.0% of rutin, trace to 11.4% of gentistic acid, and 7.4% to 46.6% of  o -coumaric acid were retained, while the retainment ratios of these components in freeze-dried samples were 84.7% to 99.0%, 76.4% to 99.3%, 90.4% to 96.1%, 39.8% to 99.3%, 24.1% to 68.4%, and 75.8% to 87.0%, respectively. The data showed that freeze-drying better preserves the nutrient and phytochemical quality of bitter melon leaves in comparison to oven-drying. Bitter melon leaf is a rich source of selected nutrients and phytochemicals.     

Nutritional potential and functional properties of sweet and bitter lupin seed protein isolates

Protein isolates were prepared from both sweet and bitter lupin seed flours by two different methods, i.e. by alkaline water extraction/isoelectric precipitation (P1) and by micellisation (MI), and studied with regard to nutritional quality and functional properties. Protein solubility of both lupin seed flours was increased as sodium chloride concentration increased up to 1.0 M, then decreased. The minimum protein solubility of bitter lupin seed flour was quite sharp at pH 4.5, while it exhibited a broad pH range of 4.3–4.9 for sweet lupin seed flour. No significant (P<0.05) differences were found between any isolates in their dry matter, fiber, lipids and moisture contents. Isolates-PI from both sources had significantly (P<0.05) higher crude protein and ash contents than their isolates-MI. Bitter and sweet isolates-PI had lower values of total essential amino acids and higher values of tyrosine, phenylalanine, threonine, tryptophan and valine than isolates-MI. There was no significant (P>0.05) difference between bitter isolates in their alkaloid contents, while both sweet lupin isolates were free of total alkaloids. Bitter lupin isolate-PI had significantly (P<0.05) lower tannins, but sweet lupin isolate-MI had a significantly (P<0.05) higher phytic acid content than other isolates. Isolates-MI from both sources had higher chemical scores than their isolates-PI. The first and second limiting amino acids were total sulfur amino acids and valine, respectively, for all types of isolates. Sweet lupin isolate-MI had a higher essential amino acid index and protein efficiency ratio than other isolates. The protein solubility index, fat absorption and emulsification capacities of both isolates-MI were significantly (P<0.05) higher than their isolates-PI. Both sweet lupin isolates had significantly (P<0.05) higher water absorption capacity than bitter lupin isolates. Sweet lupin isolate-MI had significantly (P<0.05) higher foam capacity and foam stability than other lupin isolates.     

苦瓜籽油脂肪酸成分的GC-MS分析

利用索氏抽提法提取苦瓜籽油,对苦瓜籽油的碘值、皂化值、不皂化物、熔点等理化性质进行了测定,并用氢氧化钾-甲醇室温酯化法对苦瓜籽油甲酯化,通过GC-MS对其脂肪酸成分进行分析.结果表明,苦瓜籽脂肪含量(36.81%)和蛋白含量(43.05%)都较高,苦瓜籽油常温下呈蜡状白色固体,同时有特殊的刺鼻苦涩气味.熔点为53℃,不...     

Proximate composition,histochemical analysis and microstructural localisation of nutrients in immature and mature seeds of marama bean (Tylosema esculentum) – An underutilised food legume

Marama bean (Tylosema esculentum) is a wild-growing legume adapted to semi-arid conditions in southern Africa. Both immature and mature seeds are used as food by locals and marama bean has potential as a crop plant. Physicochemical and histochemical methods were used to study the accumulation of nutrients and their localisation in immature and mature seeds. The immature seeds had a high content of moisture (67%) and protein (21%), and a low content of lipid (1.5%). At maturity, proteins formed spherical bodies that were embedded in a droplet lipid matrix. The mature seeds are exceptional as they have a high content of protein (32%) and lipid (40%) and no starch. Staining of polysaccharides indicated increases of pectin and cellulose during maturation, parallel with the general increase of cell wall thickness; however, lignin was absent. The content and distribution of protein, lipid and carbohydrates in immature and mature marama beans make this underutilised nutritive legume a prospective crop plant and interesting for food processing applications.     

Characteristics and Functionality Enhancement by Glycosylation of Bitter Melon (Momordica charantia) Seed Protein

Seeds of ripe bitter melon (Momordica charantia) contain approximately 30% protein. However, this protein, which is less functional than soy protein, may have desirable functionalities as a food ingredient after modification. Bitter melon seed protein isolate (BMSPI) was prepared under optimal extraction conditions (defatted meal to 1.3 M NaCl was 1:10 w/v; pH 9.0) and its functional properties were investigated before and after modification by glycosylation. Glycosylation was conducted at varying relative humidities (50%/65%/80%) and temperatures (40 °C/50 °C/60 °C) using a response surface central composite design. Degree of glycosylation (DG) ranged from 39.3 to 52.5%, 61.7 to 70.9%, and 81.2 to 94.8% at 40 °C, 50 °C, and 60 °C, respectively (P values < 0.0001). Denaturation temperatures of all DGs ranged from 111.6 °C to 114.6 °C, while unmodified/native BMSPI had a value of 113.2 °C. Surface hydrophobicity decreased to approximately 60% when the DG was maximal (94.8%). Solubility decreased almost 90% when the DG was maximal in comparison to the native BMSPI (62.0%). Emulsifying activity increased from 0.35 to 0.80 when the DGs were ≥80%, while emulsion stability increased from 63 to 72 min when the DGs were greater than 70%. A similar trend was observed with foaming capacity and foaming stability of the glycosylated proteins. This glycosylated BMSPI with improved emulsifying and foaming properties could be used as an ingredient in food products where such properties are required.     

Effect of maturity stages on the content of ash components in raw,frozen and canned broad beans

The aim of the present work was to determine the level of ash, potassium, phosphorus, calcium, magnesium, iron, zinc, manganese, and copper in fresh and preserved broad bean seeds at the stage of milk-wax maturity. The experiments included two broad bean cultivars, four stages of seed maturity being differentiated in each. With the higher maturity stages, the contents of ash, potassium, phosphorus, calcium, and magnesium gradually increased in fresh matter of the two cultivars. The contents of zinc and copper showed a slight decreasing tendency, while the levels of iron and manganese varied. Frozen and canned broad bean seeds of milk-wax maturity, prepared for consumption, were a valuable source of mineral compounds. The more mature the seeds, the greater were the contents of potassium, phosphorus, calcium, magnesium, and manganese, and smaller less so for copper, while the levels of iron and zinc varied. Boiled frozen seeds contained more potassium, phosphorus, magnesium, zinc, manganese, and copper than canned products, no differences being found in the contents of calcium and iron. The dehulled seeds contained more phosphorus but less calcium than the intact ones.     

Effect of lead ions on lipids and antioxidant complex activity of Capsicum annuum L leaves,pericarp and seeds

The composition of the main lipid classes in leaves, pericarp and seeds of pepper (Capsicum annuum L), and the effect of seedlings immersion in lead and sodium acetate nutrient solutions were investigated. Lead ions accumulated mainly in leaves; in pericarp and seeds the concentration of lead was more than 10 times lower. The influence of lead ions on the leaf lipid composition was expressed most in the last stages of plant development. Treatment with lead acetate caused a decrease in the activity of the antioxidative complex in pepper seeds.     

Antioxidant properties and quantitative UPLC-MS analysis of phenolic compounds from extracts of fenugreek (Trigonella foenum-graecum) seeds and bitter melon (Momordica charantia) fruit

Freeze-dried fenugreek (Trigonella foenum-graecum) seeds and bitter melon (Momordica charantia) fruit were extracted sequentially using non-polar to polar solvents, with further separation carried out on polar extracts by molecular weight cut off dialysis. The fenugreek ethyl acetate crude extract (FGE3) demonstrated the highest antioxidant activity, in terms of Trolox Equivalents (TE), for both the DPPH (35.338 ± 0.908 mg TE/g) and FRAP (77.352 ± 0.627 mg TE/g) assays. This extract also contained the highest phenolic content, in terms of Gallic Acid Equivalents (GAE) (106.316 ± 0.377 mg GAE/g). Despite having considerably lower antioxidant activity than fenugreek, the highest antioxidant activities for bitter fruit were observed in the hexane (BME1) and methanol hydrophilic < 3.5 kDa dialysed (BME4 < 3.5 kDa) extracts, while the highest phenolic content was found in the methanol hydrophilic > 3.5 kDa (BME4 > 3.5 kDa) dialysed extract. UPLC-MS was used to quantify 18 phenolic compounds from fenugreek and 13 from bitter melon in active crude extracts. The flavonoids apigenin-7-O-glycoside (1955.55 ng/mg) and luteolin-7-O-glycoside (725.50 ng/mg) were the most abundant compounds in FGE3, while bitter melon extracts contained only small amounts of mainly phenolic acids. A further 5 fenugreek and 1 bitter melon compounds were identified in trace amounts from the same extracts, respectively.     

Antioxidant activity and total phenolic content of Agaricus brasiliensis (Agaricus blazei Murril) in two stages of maturity

The antioxidant capability and total phenolic contents of methanolic extracts of Agaricusbrasiliensis in two stages of maturity, young (YB) and mature (MB), were evaluated in this work. Four complementary assays, reducing power, radical scavenging capacity, inhibition of lipid peroxidation and chelating ability for ferrous ions were used to screen the antioxidant properties of extracts. Minor differences in the composition of phenolic compounds were detected, but the extracts showed similar antioxidant activities, except for the chelating ability for ferrous ions, higher in MB than in YB. Our results support the use of both young and mature fruiting bodies of Agaricus blazei as sources of antioxidant compounds.     

Evaluation of tomato textural mechanical properties

The texture of fresh tomatoes (Lycopersicum esculentum Mill., ‘Momotaro’) at three different stage of ripeness (mature green, pink, and red) was intensively evaluated. The double-cycle load plate compression test showed that initial firmness, average firmness, energy absorption, deformation ratio, and relaxation ratio were sensitive textural parameters for identifying the maturity stages. From a puncture test, initial firmness, average firmness, apparent modulus of elasticity, rupture force, toughness, and deformation at the rupture point were sensitive to the maturity stages. The mature unripe tomato deformed linearly as a function of force; hence, the firmness was constant. However, the fully ripe tomato firmness increased as a function of applied force. The fruit strain increased during ripening, and it was independent of fruit size. The unripe tomato was more elastic than the ripe one. The peel at the mature green stage contributed approximately 70% of the firmness of the fruit and approximately 90% at the pink stage and red stage. The rupture force by the puncture test (traditionally, peak force) was correlated well with other textural parameters, which indicated that it could be used as a firmness representative parameter, as has been used by many researchers. The degree of elasticity was a better indicator for elasticity than the relaxation ratio.     

ROLE OF CALCIUM AND CHELATING AGENTS IN REGULATING THE DEGRADATION OF TOMATO FRUIT TISSUE BY POLYGALACTURONASE

The effects of calcium ions and the chelating agents EDTA and citrate on the ability of partially-purified polygalacturonase (PG) from ripe tomato fruit to degrade polygalacturonate, preparations of isolated middle lamellae and cell walls (ML-CW), and outer pericarp tissue from tomatoes were examined. The inhibition of degradation by calcium ions was counteracted by the presence of EDTA or citrate, and these chelating agents also reduced the resistance to attack by PG on ML-CW and tomato pericarp tissue. Degradation by PG of ML-CW and pericarp tissue from all ripeness stages was stimulated by chelating agents. Susceptibility of fruit tissue containing the non-ripening (nor) gene to degradation by PG was similar to that shown by normal mature green fruit tissue. With increasing maturity of the mutant fruit, resistance to degradation declined, but not as rapidly as with normally ripening fruit. It appears that calcium associated with the ML-CW and its removal regulate the rate and extent of degradation by PG during normal tomato fruit ripening.     

Strawberry,loquat, mulberry,and bitter melon juices exhibit prophylactic effects on LPS-induced inflammation using murine peritoneal macrophages

We hypothesized the juices from strawberry, loquat, mulberry and bitter melon exhibit anti-inflammatory activities using lipopolysaccharide (LPS)-stimulated murine peritoneal macrophage cultures. Selected juices were administered as a prophylactic, postmortem or concurrent event relative to LPS stimulation to clarify the effective mechanisms. Selected fruits and vegetable juices were administered to macrophage cultures for 24 h prior to LPS stimulation (model A). Selected samples were administered to cell cultures at 24 h following LPS treatment (model B). Selected fruits and vegetable juices and LPS were simultaneously co-cultured with macrophages for 24 h (model C). The LPS-induced secretions of pro-inflammatory cytokines interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α and anti-inflammatory cytokine IL-10 were determined. The results showed that strawberry, loquat, mulberry and bitter melon administration increased IL-10 production by LPS-stimulated peritoneal macrophages in dose-dependent manners in experimental model A. Simultaneously, loquat, mulberry, and bitter melon administrations significantly (P < 0.05) decreased the levels of IL-1β, IL-6 and/or TNF-α. Administration with loquat and bitter melon to experimental model C significantly increased IL-10 production. This study suggests that strawberry, loquat, mulberry, and bitter melon juices exhibit a prophylactic effect on LPS-induced inflammation of peritoneal macrophages via increasing anti-inflammatory cytokine and/or decreasing pro-inflammatory cytokines secretions.     

Protein extraction optimisation,characterisation, and functionalities of protein isolate from bitter melon (Momordica charantia) seed

Bitter melon seeds are a rich source of protein. Optimum conditions for protein extraction from the seeds, determined using a response surface design, were at a pH 9.0 and 1.3 M NaCl. Soy protein isolate (SPI) was included for comparison. Surface hydrophobicity of bitter melon seed protein isolate (BMSPI) (690) was significantly higher than that of SPI (399). Electrophoretograms of BMSPI showed bands at 40 and 55 kDa, and at 22, 25, and 35 kDa in non-reducing and reducing buffers, respectively. BMSPI had most of the essential amino acids and hence could be considered as a high quality protein. BMSPI had a single denaturation temperature (113.1 °C) while SPI had two denaturation temperatures (78.0 and 94.8 °C). The proteins exhibited U-shaped curves with solubilities ranging from 62.0% to 67.5% for BMSPI and 86.7% to 90.1% for SPI at pH ? 7.0. BMSPI had lower emulsifying activity (0.36 vs. 0.73), foaming capacity (39.6 vs. 61.0 ml), and foaming stability (21.5 vs. 25.5 min) than had SPI.     

采后伽师瓜和86-1甜瓜果实抗链格孢菌侵染研究

以伽师瓜和86-1甜瓜为试材,通过损伤接种链格孢菌的方法,从甜瓜果实病斑直径、病程相关蛋白活性及保护酶活性三方面比较了二者之间的差异。结果表明,伽师瓜的病斑直径小于86-1甜瓜的,果皮病斑直径小于果肉。整个贮藏期间,接种链格孢菌后伽师瓜和86-1 2种甜瓜的病程相关蛋白活性和保护酶活性得到提高,在抵御链格孢菌侵染的过程中起到了重要作用。尤其在侵染中后期作用显著,且伽师瓜接种果皮和果肉活性均高于86-1甜瓜。     

In vivo and in vitro studies to identify the hypoglycaemic constituents of Momordica charantia wild variant WB24

Wild bitter melon (the wild variant of Momordica charantia L.) native to the eastern region of Taiwan has been consumed by local residents as a folk medicine for the prevention or treatment of hyperglycaemia and related diseases, yet its hypoglycaemic activities and constituents have not been scientifically characterised. Thus, WB24, a strain of wild bitter melon originating from the eastern region of Taiwan, was investigated. By cell-based screening, the fruit of WB24 was revealed to be a rich source of hypoglycaemic molecules, and the in vivo hypoglycaemic activities of selected fractions were assessed. Five triterpenes were isolated from one of the most active fractions and their ability to activate AMP-activated protein kinase (AMPK) was observed. One triterpene of the five analysed exhibited the highest activation of AMPK in an insulin-independent manner, and the AMPK-activation activity of this triterpene was greater than that of troglitazone, a thiazolidinedione-type antidiabetic medicine.     

Physico-chemical changes in sugarcane (Saccharum officinarum var yellow cane) and the extracted juice at different portions of the stem during development and maturation

A study was conducted to determine the physicochemical differences between portions (top, middle, and bottom) of sugarcane at different maturation stages (between 3 and 10 months from planting). The variety used was Saccharum officinarum var. Yellow cane. The parameters analysed were weight, diameter, yield, total soluble solids (TSS), pH, titratable acidity, sugar content (sucrose, glucose, fructose). The weight, diameter, total soluble solids (TSS) and sucrose content increased significantly (P<0.01) in all portions (top, middle and bottom) up to the end of maturity. On the other hand, titratable acidity (TA), pH, juice yield, glucose and fructose contents decreased significantly (P<0.01) during maturation. However, significant differences were also detected in weight, diameter, TSS, sugar content, pH, TA and juice yield between the different portions during maturation. Sucrose content, juice yield and TSS were found to be the most suitable indicators of maturity, while TA, glucose and fructose contents were found to be poor maturity indicators. A suitable harvesting stage was found to be between 7 and 8 months after planting.     

Accumulation and quality of storage protein in developing cowpea,mung bean and soya bean seeds

This study was carried out to compare the time course of laying down seed storage protein in three legumes viz: cowpea (Vigna unquiculata), mung bean (Phaseolus aureus) and soya bean (Glycine max) planted in two replications. Pods were harvested periodically during seed maturation and studied for changes in fresh and dry weights, total sulphur, total nitrogen and protein content. At early stages of development crude protein formed about one-third of dry weight in the legumes but decreased to about one-quarter at maturity. The total sulphur which formed a substantial amount of the sulphur amino-acids in mature seeds did not change much in mung bean and cowpea but increased by about 24% from 20 to 69 days after flowering (DAF) in soya bean. Storage protein accumulation was very rapid between 10 and 14 DAF (10.4% day^?1) in mung bean, 7 and 14 DAF (12.9% day^?1) in cowpea and between 20 and 30 DAF (9.4 day^?1) in soya bean. Thereafter, protein accumulation declined slightly and gradually approached zero at time of seed maturity. The sulphur-to-nitrogen ratios gradually increased with maximum values in the mature seeds. Although seed protein content and quality (on S/N ratio basis) were highest in soya bean, accumulation of storage protein seemed to be faster in cowpea than mung bean and soya bean during seed maturation.     

Antioxidant properties of durian fruit as influenced by ripening

The antioxidant properties of durian (Durio zibethinus Murr., cv. Mon Thong) at different stages of ripening were investigated using fluorometry, UV spectroscopy, and HPLC/DAD analyses. Total polyphenols, flavonoids, anthocyanins and flavanols in ripe durian were significantly higher (p < 0.05) than in mature and overripe fruits. Free polyphenols and flavonoids were at lower levels than hydrolyzed ones. Caffeic acid and quercetin were the dominant antioxidant substances in ripe durian. In these fruits, methanol extracts contained a relatively high capacity of 74.9 ± 7.1% inhibition using β-carotene-linoleic acid assay. Ferric-reducing/antioxidant power (FRAP) and cupric-reducing antioxidant capacity (CUPRAC) assays supported this finding. The correlation coefficients between polyphenols and antioxidant capacities of durian samples with all applied assays were about 0.98. In conclusion, the bioactivity of ripe durian was high and the total polyphenols were the main contributors to the overall antioxidant capacity.     

Assessment of Indigo (Polygonum tinctorium Ait.) water extracts’ bioactive compounds,and their antioxidant and antiproliferative activities

There are a few investigations on Indigo (Polygonum tinctorium Ait.), as a medicinal plant. Therefore, the aim of this study was to assess the contents of bioactive compounds, antioxidant and antiproliferative activities and to compare with another medicinal plant Prolipid. It was found that the bioactive compounds from different parts of Indigo water extracts varied (P < 0.05): polyphenols and flavonoids were significantly higher in Prolipid, flavanols in Indigo seeds, and vitamin C similar in Indigo leaves and Prolipid. The antioxidant activity by ABTS, FRAP, CUPRAC and DPPH assays was significantly different (P < 0.05): the highest in Prolipid, following by Indigo mature leaves. DPPH kinetic measurements compared, distinguished and discriminated the antiradical activity among Indigo and Prolipid water extracts by multivariate analysis. The interaction between polyphenol extracts of Indigo mature leaves and BSA showed that Indigo has a strong ability, as other medicinal plants, to quench the intrinsic fluorescence of BSA by forming complexes. In conclusion, for the first time Indigo mature leaves were analyzed and compared with widely consumed Prolipid. The relatively high content of bioactive compounds, positive antioxidant, fluorescence and antiproliferative properties of Indigo justify the use of this plant as a new source of valuable antioxidants.