柱前衍生-高效液相色谱法测定野芭蕉不同部位的18种氨基酸含量

氨基酸是构成蔬菜口感的主要成分,蔬菜品质与其成分和含量密切相关。为更好地开发野芭蕉资源,采用柱前衍生-高效液相色谱法测定野芭蕉芯、野芭蕉花、野芭蕉苞片的水解氨基酸组成。结果显示,野芭蕉3个部分均含18种氨基酸,总含量均大于33 mg/g,其中野芭蕉苞片的氨基酸总含量最高;野芭蕉3个部分均含8种必需氨基酸,野芭蕉芯和芭蕉苞片的必需氨基酸含量占总氨基酸含量的比例均大于37%;野芭蕉3个部分的甜味氨基酸与鲜味氨基酸总含量远高于苦味氨基酸含量,药用氨基酸含量占总氨基酸含量的比例均大于70%。野芭蕉含有丰富氨基酸,可以作为新资源食品开发。     

Effect of ripening on some physicochemical properties of cooking banana (Musa ABB Cardaba) pulp and flour

Cardaba banana (Musa ABB) pulp and flours were evaluated for changes in some physicochemical properties during ripening. Compositional changes in the pulp showed that ripening significantly (P < 0.05) increased the crude protein (2.48–9.88%), fat (1.33–4.67%), crude fibre (0.80–0.93%), ash (1.66–2.32%) and Vitamin C (12.60–24.28%), while carbohydrate and tannin reduced. Mineral composition varied, following this trend: K > Mg > P > Na > Zn. pH and ‘whiteness’ reduced, while yield, softness index and pulp/peel ratio increased significantly (P < 0.05). Pasting and functional properties of the flours were lowered, however, ripening enhanced better pasting properties. Flours from stages 1–7 could be used as binders, emulsifiers and thickeners, while flours from stages 5–7 may be useful as aerating agents and in preparation of baby formulas and flours from stages 1–2 may be used in bakery products. This investigation proposes the utilisation of the Cardaba banana flour as an industrial raw material and a good substitute to potato, corn or tapioca starches.     

Extending the shelf‐life of bananas with 1‐methylcyclopropene and a chitosan‐based edible coating

BACKGROUND: The marketability of bananas over long distances has been limited due to their highly perishable nature and sensitivity to ethylene. To increase the shelf‐life several alternatives have been tested in attempts to maintain quality characteristics. We evaluated the effects of 1‐methylcyclopropene (SmartFresh^SM, 1‐MCP) and a chitosan‐based edible coating (FreshSeal^®, EC), applied alone or combined, on bananas at ripeness stage 3. All fruits were stored for 8 days at 22 °C, 85% RH. Color development, weight loss, firmness, physiological, sensory and chemical variables were evaluated. RESULTS: After 3 days, control and EC‐treated fruits were completely yellow (°Hue = 90), while 1‐MCP treated fruits alone and combined with EC were still showing some green colorations on tips and neck of fingers. After 7 days, fruits treated with the combination (EC + 1‐MCP) reached a Hue value of 90. Firmer fruits were observed with 1‐MCP alone or combined with EC. A decrease of 0.15% titratable acidity and an increase of 8°Brix were observed in all treatments during the experiment. The incidence of sugar spots was delayed and diminished on fruits treated with 1‐MCP either alone or combined. Sensory results showed no adverse effects by using the 1‐MCP or the edible coating. CONCLUSION: The combined treatment of EC + 1‐MCP could be used to extend the commercial life of bananas for up to four more days. Copyright © 2009 Society of Chemical Industry     

Biocorrosion inhibition of mild steel in crude oil-water environment using extracts of Musa paradisiaca peels,Moringa oleifera leaves,and Carica papaya peels as biocidal-green inhibitors: kinetics and adsorption studies

Biocorrosion inhibition of mild steel in the crude oil-water environment was investigated in the absence and presence of Carica papaya peel extract, Musa paradisiaca peel extract, and Moringa oleifera leaf extract as potential biocidal-green inhibitors using gravimetric, polarization, and surface analysis (Inverted metallurgical microscope and Fourier transform infra-red spectroscopy) methods. Kinetics and adsorption behaviors of the extracts were determined and evaluated. Results revealed that each of the extracts functioned as biocidal-green inhibitors in the crude oil-water environment and that biocorrosion inhibition efficiency (IE%) of each extract increased with increase in extract concentration and exposure time. Maximum IE% of 97.7, 96.5, and 99.2% was achieved with Musa paradisiaca peel extract, Moringa oleifera leaf extract, and Carica papaya peel extract, respectively, at 4000?mg/l extract concentration and 35 d exposure time. Polarization studies indicated that each of the extracts acts as a mixed-type inhibitor. Mild steel susceptibility to biocorrosion was significantly reduced by each of the extracts through biofilm development suppression and extract adsorption onto the mild steel surface which obeyed Langmuir, Freundlich, Temkin, and Flory-Huggins isotherm models. Kinetics of mild steel biocorrosion inhibition followed a Monod form of kinetics (Type A). Gibbs free energy of adsorption values for Musa paradisiaca peel extract (?9.65?kJ/mol), Moringa oleifera leaf extract (?9.57?kJ/mol), and Carica papaya peel extract (?9.71?kJ/mol) showed that each extract adsorption was spontaneous and of physical adsorption.     

Isolation and Structure Investigations of Square Banana (Musa balbisiana) Starch

Starch was isolated from unripe square banana (Musa balbisiana) fruit and characterized physically and chemically. Isolation was done with a 2³ factorial design using five replicates in the central trial. Evaluated factors were: flour: solvent ratio (1:6 ‐ 1:10, w/v); sodium bisulfite concentration (0.1 ‐ 0.3%); and soaking time (30 ‐ 60 min). Optimum starch isolation in an alkaline medium was obtained with: 1:5 (w/v) flour: solvent ratio; 0.1% sodium bisulfite concentration; and 60 min soaking time. Starch yield under these conditions was 69.8% with 94.5% purity. Starch granules had an oval‐elongate shape, a size range of 24‐68 μm, and average size of 24.6 μm. Amylose content was 22.2% and amylopectin content 77.8%. Granules had a C‐type ‐ray diffraction pattern and a degree of polymerization (DP) of 3‐20 for lengths of branch chains.     

Effects of some thermal treatments on polyphenoloxidase and peroxidase activities of banana (Musa cavendishii,var enana)

Polyphenoloxidase (EC 1.14.18.1) and peroxidase (EC 1.11.1.7) activities were evaluated during cold storage of banana (Musa cavendishii, L var enana). The effects of some thermal treatments (blanching of peeled bananas, microwave treatment of banana slices and storage of banana slices at ?24°C) were studied. Inactivation of both enzymes by blanching was very effective (96–100 %) at all maturity levels. Microwave treatment showed differing efficiency depending on banana ripeness, and produced non-enzymic darkening due to Maillard reactions mainly in green and full-yellow bananas. Freezing of fruit slices without previous thermal treatment produced different effects in polyphenoloxidase and peroxidase activities. It was concluded that immersion in boiling water of peeled bananas with 70 % green/30% yellow peel colour maturity index is the optimal pretreatment for the preservation of frozen banana slices.     

Objective measurement of banana pulp colour

Two methods for determining the colour of banana pulp were compared by using either visual matching with colour charts or a portable tristimulus colorimeter. Pulp colour of ripe and unripe bananas was evaluated in both the darker central carpellary zone and the outer pulp zone near the skin of the fruit. Colour coordinates L* and b* were highly correlated (r = -0.89 and 0.87 respectively) with the visual matching colour charts, the central carpellary region giving higher correlations than the outer pulp zone. Results obtained show that the colour of banana pulp can be objectively measured by the combined use of L* and b* coordinates determined in the carpellary zone. The potential use of a reproducible and defined method for determining banana pulp colour is discussed.     

A comparison of time domains for software reliability models

A comparison of time domains (i.e., execution time vs. calendar time) is made for software reliability models, with the purpose of reaching some general conclusions about their relative desirability. The comparison is made by using a generic failure intensity function that represents a large majority of the principal models. The comparison is based on how well the function fits the estimated failure intensity, where the failure intensity is estimated with respect to both kinds of time. The failure intensity in each time domain is examined for trends. Failure intensity estimates are calculated from carefully collected data. The execution time domain is found to be highly superior to the calendar time domain.