Amount Of Free Amino Acids Research Articles

Growth and solute pattern of Suaeda maritima and Suaeda asparagoides in an abandoned salt field

To investigate the environmental adaptation and ecophysiological characteristics of Suaeda maritima and S. asparagoides under saline conditions, plant growth and density were analyzed according to environmental changes of habitats. The total ion content of soil decreased with time, which was caused by the predominance of exchangeable <TEX>$Na^+$</TEX> and <TEX>$Cl^-$</TEX> in the upper layers. The population of S. maritima was more densely distributed in the region with higher ion contents of <TEX>$Cl^-$</TEX>, <TEX>$Mg^{2+}$</TEX>, <TEX>$K^+$</TEX> and <TEX>$Na^+$</TEX> than the population of S. asparagoides. Both species were showed a decreased population density according to increases in plant growth. Under the conditions of a salt field, S. maritima and S. asparagoides contained high inorganic ions to maintain low water potential, but low water soluble carbohydrate contents. In the case of free amino acid, S. maritima showed an especially high proline content, and contained rather large amounts of free amino acids, whereas S. asparagoides did not. Both species showed high inorganic ion contents in the leaves, which might be a mechanism of avoiding the ionic toxicity by diluting the accumulated ionic concentration with a high ratio of water content to dry weight. This result suggests that S. maritima seems to adapt to saline conditions by accumulating proline in addition to inorganic ions. S. asparagoides seems to adapt by osmoregulation processes, using inorganic ions rather than free amino acids.

Hydrolysis degree, peptide profile and phenylalanine removal from whey protein concentrate hydrolysates obtained by various proteases

SummaryThe action of various proteases was tested for preparing whey protein concentrate (WPC) hydrolysates with high degree of hydrolysis (DH), appropriate peptide profiles and reduced phenylalanine (Phe) content. The peptide profile analysis included the fractionation of hydrolysates by size‐exclusionHPLC. The rapid correct fraction area method was used to quantify the components of the chromatographic fractions. Activated carbon (AC) was used to remove Phe, and its efficiency was evaluated by measuring the amount of Phe by second‐derivative spectrophotometry. The results showed that theDHofWPChydrolysates increased and that the protease fromAspergillus oryzaeyielded the highestDHvalue. This protease also produced the best peptide profile, that is, the highest di‐ and tripeptide content (16.14%), the highest amounts of free amino acids (18.43%) and the lowest amount of large peptides (18.76%). The proteases from bothA. oryzaeandBacillus subtilisproduced the highest Phe removals (79.0 and 77.8%, respectively).

Impact of selected coagulants and starters on primary proteolysis and amino acid release related to bitterness and structure of reduced-fat Cheddar cheese

Despite substantial research, it is still difficult to produce high quality reduced-fat Cheddar cheese. The objective of this study was to investigate how two coagulants, bovine chymosin (BC) and camel chymosin (CC) having different proteolytic activities and two starter cultures, an O-culture (O) and a thermophilic strain of Lactobacillus plus O-culture (OLb) having different abilities to release amino acids, contribute to the structure and flavour development in reduced-fat Cheddar cheese. Cheeses manufactured using the four combinations of coagulants and cultures were analysed during a 28-week ripening period for the composition of casein, peptides, free amino acids, rheological properties and for sensory properties at end of ripening. Cheeses with CC, showed less extensive primary proteolysis, lower levels of bitterness and higher stress at fracture, which correlates to a harder structure. Whereas cheeses with BC had a higher amount of peptides released by chymosin, e.g. the bitter peptide β-casein (f193–209) or by starter proteases from the chymosin-produced peptide αs1-CN (f1–23). BC cheeses were also judged to be softer by the sensory panel. Cheeses containing the OLb-culture had a higher amount of free amino acids and lower strain at fracture, which correlates to a shorter structure, and the peptide profiles of cheeses produced with BC and CC were rather similar after 28 weeks in contradiction to cheeses with O-culture. Replacing the traditional coagulant BC with CC reduced bitterness but increased hardness of the reduced-fat Cheddar cheese. Replacing O- with OLb-culture also reduced bitterness but resulted in a shorter structure. The results highlight tools which could be employed to alter primary proteolysis and amino acid release, respectively, for the optimisation of flavour and structure of reduced-fat cheese.

The effect of molecular weights on the survivability of casein-derived antioxidant peptides after the simulated gastrointestinal digestion

Abstract A two-stage in vitro gastrointestinal (GI) digestion model was used to assess the survivability of antioxidant peptide fractions with different molecular weights (MW). Research on MW distribution showed that peptides above 3000 Da were more easily digested by gastric digestion than those below 3000 Da. And peptides tended to be more hydrolyzed by intestinal digestion than by gastric digestion. Determination of free amino groups suggested that peptide bonds in the peptides above 3000 Da were more inclined to be cut off during the GI digestion. However, the amount of free amino acid (AA) increased as the MW decreased and accounted for 30%–40% (w/w) of the GI digests. The peptides below 1000 Da exhibited the best initial and surviving antioxidant activities in 2, 2′-azinobis (3-ethylbenzothiszoline-6-sulphonic acid) diammonium salt (ABTS + ), hydroxyl radical scavenging and ORAC value. In conclusion, casein-derived antioxidant peptides below 1000 Da were a promising antioxidant administered orally. Industrial revelance: Numerous products are already on the market or under development by food companies, exploiting the potential of food-derived bioactive peptides. To exert physiological effects in vivo, bioactive peptides must survive the gastrointestinal (GI) digestion, and then reach their target sites after absorption. So far, only a few among the numerous bioactive peptides displaying activities in vitro have been proven effective in vivo. The real bioavailability of quite an amount of marketed products containing bioactive peptides is unclear. However, our research conducted further examination of bio-accessibility of casein-derived antioxidant peptides and assessed the effect of MW on the survivability of casein-derived antioxidant peptides after the simulated GI digestion. The survivability of peptides was above 60% after the GI digestion. And the casein-derived peptides below 1000 Da exhibited the best initial and surviving antioxidant activities. The enriched antioxidant peptide fraction above could be a promising candidate for dietary supplements and nutraceuticals with good GI survivability and bio-accessibility.

Concentration of Free Amino Acids in Human Milk of Women with Gestational Diabetes Mellitus and Healthy Women

It is generally agreed that breastfeeding has a positive effect on the metabolic situation in diabetic mothers. However, negative long-term effects are described for breastfed offspring of diabetic women. It is unknown if the composition of free amino acids (FAAs) in breastmilk of women with gestational diabetes mellitus (GDM) differs from that in milk of healthy women. We studied the amount of FAAs in breastmilk of women with GDM and women with normal glucose tolerance (NGT). Human milk samples of 68 women (21 GDM and 47 NGT) were analyzed. Contents of FAAs in milk samples, obtained within the first 4 days after delivery (colostrum) and 6 weeks later (mature milk), were analyzed using high-performance liquid chromatography. Total amounts of FAAs in colostrum and in mature milk were compared between the groups. The impact of maternal age, body mass index (BMI), gestational age at birth, birth weight, and diagnosis of GDM on the total amount of FAAs was evaluated. Overall, the total amount of FAAs increased significantly from colostrum to mature milk in both groups (p<0.001). The total amount of FAAs did not significantly differ between GDM and NGT in colostrum and in mature milk (1,560 μmol/L vs. 1,730 μmol/L and 2,440 μmol/L vs. 2,723 μmol/L, respectively). No significant influence on the total amount of FAAs at both measurements of maternal age, BMI, gestational age at birth, birth weight, and diagnosis of GDM could be observed by regression analyses. The content of FAAs of human milk does not significantly differ between women with GDM and women with NGT.

Free Cysteine Modulates the Conformation of Human C/EBP Homologous Protein

The C/EBP Homologous Protein (CHOP) is a nuclear protein that is integral to the unfolded protein response culminating from endoplasmic reticulum stress. Previously, CHOP was shown to comprise extensive disordered regions and to self-associate in solution. In the current study, the intrinsically disordered nature of this protein was characterized further by comprehensive in silico analyses. Using circular dichroism, differential scanning calorimetry and nuclear magnetic resonance, we investigated the global conformation and secondary structure of CHOP and demonstrated, for the first time, that conformational changes in this protein can be induced by the free amino acid l-cysteine. Addition of l-cysteine caused a significant dose-dependent decrease in the protein helicity – dropping from 69.1% to 23.8% in the presence of 1 mM of l-cysteine – and a sequential transition to a more disordered state, unlike that caused by thermal denaturation. Furthermore, the presence of small amounts of free amino acid (80 µM, an 8∶1 cysteine∶CHOP ratio) during CHOP thermal denaturation altered the molecular mechanism of its melting process, leading to a complex, multi-step transition. On the other hand, high levels (4 mM) of free l-cysteine seemed to cause a complete loss of rigid cooperatively melting structure. These results suggested a potential regulatory function of l-cysteine which may lead to changes in global conformation of CHOP in response to the cellular redox state and/or endoplasmic reticulum stress.

NMR comparison of in vitro digestion of Parmigiano Reggiano cheese aged 15 and 30 months

The content of essential amino acids is an important aspect for determining the nutritional value of food proteins, but their digestibility is also a key property, deeply affected by food processing. The production of Parmigiano Reggiano cheese is closely related to the nutritional quality of the final product; in particular the high digestibility of its proteins is claimed to be proportional to cheese aging. Two different kinds of Parmigiano Reggiano, young (aged 15 months) and old (aged 30 months), were separately digested using an in vitro system that simulates digestive processes in the mouth, stomach and small intestine. Samples were collected at different stages of digestion and the process of protein hydrolysis was explored and compared by low-field (LF) and high-resolution (HR) NMR, together with other biochemical methods. HR-NMR allowed to simultaneously observe the quantity of free amino acids, peptides and proteins, also giving for these latter qualitative information about their dimension. LF-NMR, instead, gave the possibility to observe digestion with no treatments whatsoever, thus representing a technique suitable for on-line measurements. The results pointed out that cheeses with different aging times, although starting from distinct initial compositions, conclude digestion in a similar way, in terms of free amino acids and small organic compounds, but evolve with different kinetics of hydrolysis and peptide formation, discriminating the young from the old cheese.

Effect of different nitrogen forms on the growth and quality of different potherbs

Effects of different nitrogen forms on the growth and quality of the three potherbs including Gynuradivaricata(L.) DC.,Talinum paniculatum(Jacq.) Gaert.and Gynurabicolor(ROXB.)DC was studied under solution culture with optimal nitrogen concentration(12 mmol/L).The main results are as follows: ①The fresh weight of shoot of the three potherbs increases gradually with the decrease of the ratio of NH4+∶NO3-under the condition of optimal nitrogen concentration.When the ratio of NH4+∶NO3-is 25∶75,the maximum fresh weight is obtained for Gynuradivaricata and Talinum paniculatum,and the maximum fresh weight is obtained for Gynurabicolor when the ratio of NH4+∶NO3-is 0∶100.The maximum dry weight is obtained for Talinum paniculatum and Gynurabicolor when the the ratio of NH4+∶NO3-ratio is 25∶75,and the maximum dry weight is obtained for Gynuradivaricata when ratio of NH4+∶NO3-is 0∶100.②The contents of nitrate and nitrite of the three potherbs increase dramatically and the total amount of free amino acids decreases with the decrease of the ratio of NH4+∶NO3-.As a result,appropriate increase of ammonium application would benefit the decrease of the content of nitrate in potherbs.③The content of V–C,soluble sugar and soluble protein are in high level when the the ratio of NH4+∶NO3-is 75∶25 or 50∶50.

Antioxidant activities and antioxidative components in the surf clam, Mactra veneriformis

Aqueous (ET1) and alcoholic (ET2) extracts from Mactra veneriformis were studied for their antioxidant potentials using various in vitro assays. The ET2 was fractioned into four parts according to the polarity of the extractive medium, viz. ET2-p (petroleum ether), ET2-e (ethyl acetate), ET2-n (n-butanol) and ET2-w (water). Among the four fractions, ET2-w showed the strongest reducing power, and highest 2,2 diphenyl-1-picrylhydrazyl (DPPH) scavenging and metal chelating activities, while the ET2-p possessed higher hydroxyl radical scavenging activities. It was found that ET2-w had large amounts of free amino acids and oligosaccharides, while ET2-p contained a large amount of unsaturated fatty acids. We conclude that amino acids, oligosaccharides and unsaturated fatty acids all contribute to the antioxidant activity of M. veneriformis. In order to elucidate the above, antioxidative components involved in the antioxidant activities were also detected. It was found that amino acids and carbohydrates were the major components of ET2-w. The amino acids were Tau (0.26%), Tyr (0.38%), Met (0.31%), Cys (0.38%), Arg (1.79%) and so on, while carbohydrates were oligosaccharides that were composed of disaccharides and trisaccharides. The unsaturated fatty acids were the major components of ET2-p, which contained a high amount of docosahexaenoic acid (9.03%) and eicosapentaenoic acid (18.49%).

The Comparison of Amino Acid Content of the Hydrolysate under Extrusion Pretreatment with Non-Extrusion Pretreatment

The extrusion pretreatment was employed in the aqueous enzyme assisted extraction (EAEP) of oil process. The amount of amino acid was detected during the study. Experimental results indicated that the extrusion pretreatment contributed to the increment of free amino acid amount.

Influence of yeast strain, immobilisation and ageing time on the changes of free amino acids and amino acids in peptides in bottle‐fermented sparkling wines obtained from Vitis vinifera cv. Emir

SummaryThis paper reports the influence of yeast strain, immobilisation and ageing time on the free amino acids and amino acids in peptides of sparkling wine made by the traditional method from the Emir grape variety over a period of 365 days in vintages 2004 and 2005. Four sparkling wines were obtained from the same base wine using yeast strains (both immobilised and free Saccharomyces bayanus and Saccharomyces oviformis). The analysis of variance and cluster revealed that there were significant differences between free amino acids and amino acids in peptides due to ageing time. However, the yeast strain affected most of the free amino acids and amino acids in peptides in only the 2004 vintage. The total amount of free amino acids was higher in the wine made with the S. oviformis compared to S. bayanus. Furthermore, there were no significant differences between the use of immobilised and free yeast in cases of free amino acids and amino acids in peptides.

Free aromatic amino acids in egg yolk show antioxidant properties

Laying hens are known to be able to “bio-convert” health-promoting components from the diet into eggs. Wheat and corn are important sources of antioxidant phenolics in the human diet. Given the fact that wheat and corn are major feed ingredients of laying hens in Canada, the objectives of this study were to characterise the presence of novel phenolic compounds in egg yolk and to determine the effect of cooking methods on their content and activity. The total phenolic content of yolk extracts was 3.83 and 3.49 μmol gallic acid equivalents/g dry yolk for wheat-based and corn-based yolks, respectively. Antioxidant properties of yolk extracts were measured by the ORAC, DPPH and ABTS assays. ORAC values were 151.1 ± 26.1 and 155.9 ± 9.5 μmol TE/g for wheat-based and corn-based yolks, respectively. All cooking methods significantly reduced ( p < 0.05) the antioxidant values. Ferulic acid was detected in trace amounts and no other phenolic compounds were found. However, tryptophan and tyrosine were found to be two main contributors to the antioxidant property of egg yolk. The contents of total free amino acids were 10081.0 and 10009.5 μg/g in wheat-based and corn-based yolks, respectively; cooking methods were found to reduce significantly the amount of free amino acids.

한우육의 성분조성에 미치는 인진쑥 TMR 사료 급여 영향

본 연구에서는 제주도에서 자라는 인진쑥을 일정량 첨가한 TMR 사료를 개발하여, 이를 제주 한우에게 급여한 경우, 인진쑥의 급여가 한우등심의 성분조성에 미치는 영향을 확인하였으며, 그 결과로 고급화된 기능성 한우의 생산 가능성을 검토하였다. 대조군(control)은 인진쑥을 혼합하지 않은 비육우 사료를 급여하였고, 급여군(treatment)은 인진쑥을 혼합한 비육우 사료를 급여하였다. 한우등심의 수분, 조단백질, 조지방, 조회분 함량, 열량, 콜레스테롤 및 콜라겐은 인진쑥 급여에 의한 영향이 없었다. 무기질 함량은 대조군 및 급여군 사이에 유의한 차이가 없었으며, 총무기질 함량은 대조군 및 급여군이 각각 3,559.20 및 3,998.01 ppm으로 유의한 차이가 없었다. 비타민 <TEX>$B_1$</TEX> 및 <TEX>$B_2$</TEX>함량은 대조군 및 급여군 사이에 유의한 차이가 없었다. 구성아미노산 총량은 대조군 및 급여군이 각각 14.56% 및 13.90%로 유의한 차이가 없었으며, 유리아미노산 총량은 대조군(763.06 ppm)과 급여군(720.92 ppm) 사이에 유의한 차이가 없었다. 포화지방산은 대조군 및 급여군이 각각 42.956% 및 40.918%이고, 불포화지방산은 각각 57.043% 및 59.083%이었다. 인진쑥을 급여한 한우등심에서 유의하게 증가한 지방산은 myristic acid, myristoleic acid, pentadecenoic acid, palmitic acid 및 <TEX>${\gamma}$</TEX>-linolenic acid이었으며, 급여하지 않은 한우등심에서 많이 함유된 지방산은 arachidic acid이었다(p<0.05). TMR feed developed by adding mugwort originating from Jeju Island,was fed to Hanwoo to investigate the effects of feeding mugwort on nutritional composition, as well as the feasibility of producing Hanwoo beef with high quality and functionality. The samples for the experiment consisted of Hanwoo fed fattening cattle TMR feed without mugwort (control), and Hanwoo fed fattening cattle TMR feed with added mugwort (treatment). Feeding mugwort did not lead to a significant difference in the moisture, crude protein, crude fat, crude ash, calorie, cholesterol, and collagen contents. There was no significant difference between the control and treatment groups in mineral components. The control and treatment groups had total mineral amounts of 3,559.20 and 3,998.01 ppm, respectively. The total amount of structural amino acids did not show any significant difference between the control (14.56%) and treatment groups (13.90%). The total amount of free amino acids did not show any significant difference between the control (763.044 ppm) and treatment groups (720.885 ppm). The composition of saturated fatty acids was 42.956% for the control and 40.918% for the treatment group. Further, the composition of unsaturated fatty acids was 57.044% for the control and 59.082% for the treatment group. Myristic acid, myristoleic acid, pentadecenoic acid, palmitic acid, and <TEX>${\gamma}$</TEX>-linolenic acid were increased by feeding mugwort. Arachidic acid was contained the most among the fatty acid of Hanwoo fed feed without mugwort (p<0.05).

Enterally delivered dipeptides induce changes in small intestinal (SI) morphology and PepT1 mRNA in a Yucatan miniature piglet model of short bowel syndrome

PepT1, a di/tripeptide transporter, is preferentially maintained over free amino acid transporters in situations of gut stress. Our objective was to determine the impact of enterally delivered dipeptide-containing diets on PepT1 transporter abundance and SI adaptation in neonatal piglets with an 80% jejuno-ileal resection. A residual 100 cm of ileum was left intact. Piglets (n = 25, 10 ± 1 d old) were randomized to either: 1) control diet containing free amino acids (C), or the same diet but with equimolar amounts of free amino acids replaced by 2) alanylalanine (AA), 3) alanylgutamine (AG), 4) cysteinylglycine (CG) or 5) both AG and CG (AGCG). All pigs received TPN after surgery followed by continuous gastric infusion of test diets from d 3 to 7 at 50% of total intake (50:50 TPN:EN). Animals were killed on d 7. Residual SI mucosal mass of AG and AGCG pigs was 40% less than in C pigs (p<0.05). The CG pigs had greater villus height compared to either AA or AGCG (p<0.05). Moreover, CG pigs had greater crypt depth and PepT1 expression than AG pigs (p<0.05). Enteral provision of dipeptides impacts intestinal adaptation, but the responses are dipeptide specific. It appears that CG confers beneficial effects on gut adaptation compared to AG, although more research is needed to assess how this affects functional capacity. (Ajinomoto, CIHR). Grant Funding Source: Ajinomoto, CIHR

청국장 발효시의 성분 변화 및 펩티드의 생성

We analyzed content and peptides in order to investigate the productivity from Cheonggookjang(fast-fermented soybean paste), fermenting it for 180 hours at . Results showed that pH was 7.07 at the start and became 7.41 in 24 hours, it eventually increased to 8.63 after 180 hours. Acidity was 0.2 in 12 hours, 0.5 in 12 hours, and then remained on 0.1 thereafter. Total sugar was 1.54 mg/ at the start, but it gradually decreased to 0.76 mg/ after the lapse of 48 hours, and 1.0 mg/ in 120 hours, and finally 0.8 mg/ in 180 hours. Reducing sugar was 0.14 mg/ at the start, and 0.88 mg/ after the lapse of 24 hours, 0.64 mg/ in 48 hours, 0.26 mg/ in 72 hours, and showed no definite change untill 180 hours. The amount of free amino acid was at the start, and after the lapse of 72 hours, in 120 hours, and then it rapidly decreased to after180 hours. Absorbance of soluble protein and peptide at 280 nm was 12.4 in 48 hours, 31.12 in 120 hours, and 31.12 in 180 hours. HPLC revealed that in the fermentation process, large molecular proteins are hydrolyzed into small peptides and amino acids, and after the lapse of 48 hours the pattern became almost the same. The protease activity of Cheonggookjang was 0.011 unit/ after the lapse of 36 hours and then it decreased. The result shows as Cheonggookjang started its deamination of amino acid in 100 hours, it is desirable to produce peptide within 100 hours of its fermentation.

UPLC analysis of free amino acids in wines: Profiling of on-lees aged wines

The evolution of free amino acid (FAA) profiles intrinsic to on- lees aged white wines was determined by ultra performance liquid chromatography (UPLC™). On basis of the AccQ.Tag™ method as a commercialized amino acid analysis solution for HPLC, a new protocol for dedicated amino acid analysis using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) for pre-column derivatization was established by method transfer onto UPLC™ conditions. Since AQC derivatives enable both fluorescence (AccQ.Tag™ method) and UV detection, the performed method transfer additionally included changing to a more versatile UV detection. Emphasizing enhanced performance of UPLC™, the newly established protocol facilitated rapid and reliable separations of 24 amino acids within 23 min, hence proved to be superior compared to the original HPLC protocol due to significant improvements in resolution and reduced runtime. Applying UV detection enabled adequate quantifications of AQC amino acid derivatives at μM level (LOQs from 0.12 to 1.10 μM), thus proved sufficient sensitivity for amino acid profiling in wine samples. Moreover, this compiled methodology was successfully applied to monitor the changes of FAA concentrations in four distinct sets of on-lees aged white wines (fermented with different yeasts) at three progressing ripening periods, each (control, 3 and 6 months aging). For the control wines, the applied winery yeast significantly affected total FAA amounts (1450–1740 mg L −1). During maturation, the proceeding yeast autolysis implied a rather complex impact on FAAs, yielding total FAA excretions up to 360 mg L −1. However, the magnitude for increases of specific FAAs (up to +200%) highly depended on the individual amino acids as well as on the applied fermenting yeast. Given the overall complexity of yeast autolysis in winemaking, the application of efficient LC techniques such as UPLC™ may indeed contribute as a valuable tool in wine research for product monitoring and characterization of intrinsic developments during wine maturation.

Effect of N-stearoylethanolamine on free amino acid levels in rat plasma and liver with burn

The effect of the endocannabinoid congener N-stearoylethanolamine (NSE) on the content of plasma and liver free amino acids in burned rats was studied. The animals after the thermal burn of the skin received per os during 7 days the water suspension of NSE in the doze 10 mg/kg of body weight. In the other group of rats the suspension was applied on the wound (the concentration of NSE was 10 mg/ml). In experimental animals the total amount of free amino acids in plasma decreased after burn while the total amount of free amino acids in liver significantly increased. In burn animals the ratio of plasma and liver Phe/Tyr and Gly/Val was found to be augmented while the Fischer ratio (Ile+Leu+Val/Phe+Tyr) diminished compared with intact rats. It was shown for the first time that NSE caused normalization of the concentration of some free amino acids and of Phe/Tyr, Gly/Val ratios, and the Fischer ratio in blood plasma and liver of rats with the burn injury. Altogether, these data demonstrate that NSE possesses adaptogenic properties, and is involved in the organism response to a burn. These findings suggest possibility of NSE usage for burn treatment.

市販野菜ジュース類中の遊離アミノ酸組成

We investigated the composition of free amino acids, including free amino acids in 29 brands of commercially available vegetable juices.1) The composition of the free amino acids were similar among the 29 brands.2) The total amount of free amino acids was 153. 3±92. 1mg/100 ml (range, 68. 1 to 403. 4mg/100ml). The predominant free amino acids were glutamic acid, aspartic acid, alanine, asparagine, γ-aminobutyric acid, and arginine.3) Four of the 29 brands contained≥30mgγ-aminobutyric acid /100ml, and these brands had the common ingredients of carrot and tomato.4) A strong positive correlation was observed between the total free amino acid and glutamic acid content (r=0. 941), total free amino acid and γ-aminobutyric acid content (r=0. 951), total free amino acid and branched-chain amino acid content (r=0. 950), and between glutamic acid andγ-aminobutyric acid content (r=0. 936).

Soluble Nutrient Production During Fermentation of Three Melon Varieties in the Leaves of Musa spp, Thaumatococcus danielli and Carica papaya

The amount of soluble nutrient production (soluble sugars and free amino acids) in three varieties of melon seeds, Citrullus colocynthis (A), Cucumis melo (B) and Cucumeropsis mannii (C) during fermentation in Musa spp (M), Thaumatococcus danielli (D) and Carica papaya (P) leaves were investigated. Proximate compositions of the three varieties revealed that they were very rich in fat with variety C having the highest content (55.93%) while it was the least rich in protein (24.42%). In contrast to the fat composition, carbohydrate content was the least in all three varieties with variety B having the highest (16.31%) and A the least (7.86%). Variety A, however, was the richest in protein (37.14%) while C had the lowest value (24.42%). Fermentation increased the amounts of free amino acids in all varieties of melon and in all leaf types. Varieties fermented in Musa spp leaf gave the highest amounts with C having 275 ± 19.6 mg/g dry weight, B and A having 240 ± 19.6 mg/g and 155±9.8 mg/g respectively. Varieties fermented in Thaumatococcus danielli had higher retention levels of free amino acids than those fermented in Carica papaya . Fermentation however decreased the total soluble sugar levels in all three varieties of melon and in all leaf types. On the average, varieties fermented in Musa spp gave highest retention levels of soluble sugars with C (720 ± 29.3 mg/g dry weight), B (567 ± 13.72 mg/g), A (295±9.8 mg/g). Enzymatic activities (amylase, proteinase and lipase) increased throughout fermentation in all varieties of melon and in all leaf types, with proteinase being the highest as observed in variety B (10.33 ± 1.67, 10.00 ± 1.96 and 9.67±1.5 mg tyrosine/min) for all leaves. Amylase activity followed the same trend (0.252 ± 0.03, 0.236 ± 0.02 and 0.224 ± 0.02 mg maltose/min). Lipase activity was highest in variety A (0.53 ± 0.003 mg oleic acid/min) than in B and C (0.48 ± 0.02 and 0.49 ± 0.002 mg/g) respectively. Of the three types of leaves used in the fermentation process, Musa spp and Thaumatococcus danielli were observed to serve as better materials for fermentation while melon varieties C and B were better suited for fermentation into condiment.

Physiochemical changes in sunberry (Physalis minimaL.) fruit during growth and ripening

Introduction . Physalis minima is a widespread, quick-growing and high fruit-yielding annual herb belonging to the family Solanaceae. However, like many other underutilized fruit-bearing plants, P. minima is poorly studied and its nutritional potential is unknown. Since the edible sunberry is said to be a rich source of vitamin C, we studied the physiochemical changes during its fruit growth and ripening. Materials and methods . The changes in the physiochemical properties, such as pH, total soluble solids, titrable acidity, chlorophylls, carotenoids, carbohydrates (reducing sugars, non-reducing sugars, total sugars and starch), free amino acids, total proteins, total phenols, ascorbic acid, ethylene, and respiration and the activities of hydrolytic enzymes (amylase and invertase), antioxidant enzymes (catalase and peroxidase), and cell wall-degrading enzymes (cellulase, polygalacturonase and pectinmethylesterase), were analyzed in the fruit of sunberry at five sequential stages, viz. , the young, premature, mature, preripe and ripe stages. Results and discussion . A gradual increase in the pH and total soluble solids occurred throughout the growth and ripening of sunberry fruit, while its titrable acidity increased up to the preripe stage and thereafter declined. A decreasing trend in the chlorophylls occurred simultaneously with an increase in the quantity of carotenoids. As the sunberry fruit proceeded towards ripening, the amount of its total starch decreased, with a concomitant sharp increase in the quantity of its reducing sugars, non-reducing sugars and total sugars. An increase in the quantity of free amino acids, proteins and phenols also occurred during the growth and ripening of the fruit, and the quantity of ascorbic acid increased at the mature stage. Moreover, sunberry fruit also exhibits a climacteric behavior with increased ethylene production and rate of respiration. The specific activity of amylase increased throughout the growth period of sunberry, but that of invertase decreased after maturity until ripening. The catalase and peroxidase enzymes showed higher activity, indicating better radical scavenger properties, while cellulase, polygalacturonase and pectinmethylesterase tended to remain at lower levels. Conclusion . The fruit of P. minima are nutritive and a rich source of sugars, starch, free amino acids, proteins, total phenols and ascorbic acid. They are metabolically active, showing a high specific activity of hydrolyzing and antioxidant enzymes, while the activity of cell wall-degrading enzymes is relatively low, indicating a better postharvest storage life.