Extraction optimization and profile analysis of oligosaccharides in banana pulp and peel

This study evaluated the effect of ethanol concentration (EC, 0–70%) and temperature (25–75 °C) on the oligosaccharides extraction from ripe banana pulp, as well as the profile of mono‐, di‐, galacto‐, fructo‐, malto‐ and xylooligosaccharides in ripe banana pulp and peel. According to response surface plots, EC of 52% (vol/vol) and 75 °C provided the maximum oligosaccharides extraction from banana pulp. High‐performance anion exchange chromatography coupled to pulsed amperometric detection showed the presence of glucose, fructose, sucrose, maltose, arabinose, 1‐kestose, xylopentaose, and xylohexaose in banana pulp and glucose, fructose, sucrose, 1‐kestose, maltotriose, xylopentaose, and xylohexaose in banana peel. Banana pulp and peel showed 6.47 and 1.42 mg/g dw of total oligosaccharides, respectively. The chromatographic analysis showed fructo‐ and xylooligosaccharides as the main banana oligosaccharides. Finally, banana can contribute to the intake of sugars and prebiotic oligosaccharides.

Practical applications

The extraction is the first step in the evaluation of the plant composition and several factors influence the recovery of the target compound. Oligosaccharides present a wide variety of applications in food science and industry and they are extensively studied in fruits metabolism. Methods with extraction conditions optimized and chromatography conditions well‐defined are very important to obtain reliable results. Furthermore, banana is one of the most consumed and processed fruits around the world and, consequently, the extraction procedure and analytical technique showed in this study can be helpful for quality control of banana and their products.     

Yield,characteristics and composition of banana juice extracted by the enzymatic and mechanical methods

A comparative study of the enzymatic and mechanical banana juice extraction methods and the respective juices produced was carried out using Kayinja bananas (ABB genotype) imported from Uganda. In the enzymatic extraction process, macerated ripe banana pulp was incubated with a commercial enzyme preparation (Pectinex Ultra SP‐L) at 50 °C for 2 h. In the mechanical extraction process the ripe banana pulp was mixed with stretched strips of polythene and worked with a dough mixer at room temperature for 20 min (on average) until the juice appeared. Significantly (p < 0.05) higher ‘pure’ juice yield (604 g kg^?1 pulp) was obtained with the enzymatic method than with the mechanical method (541 g kg^?1 pulp). However, adding water to the spent pulp from the mechanical process and extracting dilute juice improved the juice yield to 757 g kg^?1 pulp. The enzyme‐extracted juice had significantly (p < 0.05) higher soluble solids, titratable acidity, fructose, glucose, total nitrogen, density and mineral potassium. However, the mechanically extracted juice had significantly higher sucrose, pH and viscosity. Although the mechanical extraction process suffers from occasional juice extraction failures, it offers an opportunity to extract banana juice without excessive energy expenditure, and the juice produced is wholesome with a superior flavour to that produced by the enzymatic method. © 2002 Society of Chemical Industry     

DEVELOPMENT OF A SWEETENER FROM BLACK PLUM (VITEX DONIANA) FRUIT

The Black plum (Vitex doniana) fruit was studied in respect of the chemical composition of its edible pulp, and syrup produced by concentration of extracted juice. Organoleptic evaluation was also conducted on the developed syrup. The results show that the edible pulp of the fruit is acidic (PH 5.20), high in moisture (67.9%), sucrose (12.5%) and reducing sugar (7.3%), and fairly rich in vitamin C (28.5 mg/100 g). Temperature of water used for extracting juice from the pulp correlated positively with soluble solids (r=0.86), titratable acidity (r=0.91) and negatively with vitamin C (r=?0.61). The syrup contained higher reducing sugars (51.7%), lower moisture (25.0%), but similar sucrose (12.9%) content compared to the pulp. The soluble solids of the extracted juice and consequently the yield of the syrup varied with water temperature. An optimum temperature of 80°C gave 20% (w/w) syrup per pulp. The syrup compares favorably with sucrose in sensory properties in model foods.     

Flavor Release from a Banana Soft Drink Complex Model System: Evaluation of the Efficiency of Different Adsorbents for Trapping the Released Volatiles During Storage

The main objective of the present study was to evaluate the release of aroma compounds from a banana soft drink complex model system in comparison with their release from simple model systems, each contains individual food ingredients. The effect of different food ingredients (sweeteners and thickeners at different concentrations), used in formulation of the soft drinks, on flavor release from simple model systems containing banana flavor was evaluated separately. The optimum release of isoamyl acetate (the most potent odorant of banana aroma) was observed at a concentration of 10% of each investigated sweetener (sucrose, glucose, and corn syrup). Pectin and xanthane showed the highest release at a concentration of 2.5 and 0.8% w/w, respectively. The level of each ingredient that showed the optimum release of isoamyl acetate was selected and used in formulation of a banana soft drink complex model system. The released volatiles were trapped by tenax and activated carbon. The gas chromatographic-mass spectrometric analysis revealed a gradual decrease (p < 0.05) in the volatile compounds release from the complex banana soft drink model system during storage for 90 days. However, the total content of the volatiles adsorbed by activated carbon trap was higher than that trapped by tenax. The percentage of isoamyl acetate to total volatiles (isoamyl acetate/total volatiles %) was calculated for each sample during storage. A distinct linear correlation was found between the calculated values and storage time (r = 0.97 and 0.92 for volatiles trapped by tenax and activated carbon, respectively). Sample stored for 60 days showed the highest value. These findings confirmed the results of aroma sensory evaluation.     

香蕉葡萄糖浆的制备

研究用香蕉提取淀粉来制备葡萄糖浆。香蕉淀粉在抗高温α-淀粉酶的水解下可得麦芽糊精。香蕉麦芽糊精在淀粉葡萄糖苷酶和支链淀粉酶的作用下,经60℃,24h糖化后可制得葡萄糖浆。结果表明:香蕉葡萄糖浆和一般商用葡萄糖浆的化学和物理特性基本相同,但前者的颜色更清晰,适宜于食品工业的应用。     

碎米制备高果糖浆的工艺研究

研究碎米制备高果糖浆的工艺,主要对碎米葡萄糖异构化制取果葡糖液、钙型树脂分离果糖和葡萄糖获得高果糖浆的工艺进行优化。通过单因素和正交试验,得到制取果葡糖液的最优条件：异构酶加酶量9mg/g 碎米葡萄糖、pH7.5、反应温度70℃、反应时间35h;通过正交试验,得到树脂分离制取高果糖浆的最优条件：分离温度70℃、糖液体积分数20%、洗脱液流速4mL/min、进料量40mL。在优化条件下获取的高果糖浆果糖含量为89.64%。     

Maillard Reaction Products as Encapsulants for Fish Oil Powders

The use of Maillard reaction products for encapsulation of fish oil was investigated. Fish oil was emulsified with heated aqueous mixtures comprising a protein source (Na caseinate, whey protein isolate, soy protein isolate, or skim milk powder) and carbohydrates (glucose, dried glucose syrup, oligosaccharide) and spray‐dried for the production of 50% oil powders. The extent of the Maillard reaction was monitored using L*, a*, b* values and absorbance at 465 nm. Encapsulation efficiency was gauged by measurement of solvent‐extractable fat and the oxidative stability of the fish oil powder, which was determined by assessment of headspace propanal after storage of powders at 35 °C for 4 wk. Increasing the heat treatment (60 °C to 100 °C for 30 to 90 min) of sodium caseinate‐glucose‐glucose syrup mixtures increased Maillard browning but did not change their encapsulation efficiency. The encapsulation efficiency of all heated sodium caseinate‐glucose‐glucose syrup mixtures was high, as indicated by the low solvent‐extractable fat in powder (<2% powder, w/w). However, increasing the severity of the heat treatment of the sodium caseinate‐glucose‐glucose syrup mixtures reduced the susceptibility of the fish oil powder to oxidation. The increased protection afforded to fish oil in powders by increasing the temperature‐time treatment of protein‐carbohydrate mixtures before emulsification and drying was observed irrespective of the protein (sodium caseinate, whey protein isolate, soy protein isolate, or skim milk powder) and carbohydrate (glucose, glucose/dried glucose syrup, or oligosaccharide/dried glucose syrup) sources used in the formulation. Maillard reaction products produced by heat treatment of aqueous protein‐carbohydrate mixtures were effective for protecting microencapsulated fish oil and other oils (evening primrose oil, milk fat) from oxidation.     

Inhibitory effect of rice bran extract on polyphenol oxidase of potato and banana

Rice bran was extracted with water and its effects on potato and banana polyphenol oxidase (PPO) were investigated. Rice bran extract (RBE), conc. 0.3 g mL^?1, exhibited PPO inhibition in potato and banana PPO with % inhibition of 69.31% and 47.63%, respectively (P ≤ 0.05). RBE showed a concentration‐dependent inhibition on potato and banana PPO. RBE (conc. 0.3 g mL^?1) inhibited potato PPO higher than ascorbic acid, citric acid, NaCl and EDTA (final conc. 20 mg L^?1); and it also inhibited banana PPO higher than citric acid, NaCl and EDTA (final conc. 20 mg L^?1), respectively. The combination of RBE with citric acid or ascorbic acid appeared to be additive inhibitory effect on banana and potato PPO. Kinetic study of the inhibition on potato and banana PPO by RBE showed that RBE was a mixed‐type inhibitor; however, RBE appeared to be able to act directly on enzyme structure rather than substrate structure.     

THE EFFECT OF FERMENTATION ON CASSAVA STARCH MICROSTRUCTURE

The effect of glucose syrup addition on sour cassava starch fermentation was studied on cassava starch from three locations in Santa Catarina State (Brazil), following four treatments: traditional, 0.10, 0.25 and 0.50% of glucose syrup added to total cassava suspension volume. A glucose syrup concentration of 0.50% contributed to doubling fermentation yield. The objective of this work was to observe the effect of the cassava starch fermentation process on starch granule microstructure, as compared with industrial processing. Micrography was performed using a scanning electron microscope, at 2000× magnification. Fermentations with 0.50% glucose syrup presented the greatest effects on starch granule microstructure.     

月饼糖浆熬制工艺条件对其质量的影响

在单因素试验基础上,采用正交试验,对月饼糖浆熬制工艺条件进行了研究。结果表明:加水量和柠檬酸添加量是影响糖浆浓度和转化率的主要因素,而影响糖浆质量的主要因素是熬制时间,其次是柠檬酸添加量和熬制温度,加水量影响最小。熬制糖浆最佳工艺条件为:柠檬酸添加量1.1%、加水量60%、熬制时间23min、熬制温度116℃,糖浆糖浓度92%,化率94.2%。     

Chemical Evaluation of Musa ‘Bhimkol’ as a Baby Food

The edible pulp of Musa ‘Bhimkol’ was analysed for certain organic compounds and mineral nutrients at two stages of development of the fruit to evaluate it as a baby food. Energy value and carbohydrate concentration increased substantially as the fruit ripened so that 16.8% of the energy requirement (recommended daily allowance, RDA) for six-month-old infants would be met by 100 g of the fresh pulp. Although vitamin C content decreased at maturation, 7% of the RDA would be provided by 100 g fresh pulp. The fruit was found to be very rich in macro- and micronutrients, and 100% of the six-month infants RDA for K, Mn, Zn and Se would be satisfied with 100 g of fresh pulp. This amount of pulp would also provide 86%, 57%, 24% and 12% respectively of the Mg, Cu, Fe and P RDA. P and Mg were found to be more highly concentrated in the ripe than in the unripe fruit whereas the reverse was the case for Ca and Se. Aspartic acid, glutamic acid and leucine were the major amino acids in the ripe fruit and respectively constituted 13.1, 12.5 and 7.9%, of the total. The concentration of essential and non-essential amino acids was much higher than that in a commercial banana. Twelve of the 17 amino acids analysed were more concentrated in the mature compared with the green fruit, and 11 of these were an order of magnitude higher than in M paradisiaca L banana. The results of the present study demonstrate that Musa ‘Bhimkol’ is a nutritious baby food.     

Stimulation of glucose uptake by Musa sp. (cv. elakki bale) flower and pseudostem extracts in Ehrlich ascites tumor cells

BACKGROUND: Glucose uptake study plays a major role in diabetes research. Impaired glucose uptake has been implicated in the development of hyperglycemia during diabetes. Banana plant is known for its anti‐diabetic properties and our earlier report revealed that banana flower and pseudostem of Musa sp. cv. elakki bale is beneficial during diabetes in rat models. The present study was designed to evaluate the potential effect of banana flower and pseudostem extracts on glucose uptake in Ehrlich ascites tumor (EAT) cells using 2‐[N‐(7‐nitrobenz‐2‐oxa‐1,3‐diazol‐4‐yl)amino]‐2‐deoxy‐D ‐glucose (2‐NBDG), a fluorescent analogue of 2‐deoxyglucose. RESULTS: Methanol and aqueous extracts of banana flower and pseudostem were more potent in promoting glucose uptake in EAT cells, in comparison to acetone and ethanol extracts. At 20 µg dosage, highest net glucose uptake was observed in aqueous extracts of banana flower (18.17 ± 0.43 nmol L^?1) and pseudostem (19.69 ± 0.41 nmol L^?1). Total polyphenol content was higher in methanol (9.031 ± 0.036 g kg^?1) and aqueous (6.862 ± 0.024 g kg^?1) extracts of banana flower compared to pseudostem, which were 0.442 ± 0.006 and 0.811 ± 0.011 g kg^?1, respectively. CONCLUSION: Banana flower and pseudostem extracts are able to promote glucose uptake into the cells, presumably through glucose transporters 1 and 3, which could be beneficial in diabetes. Glucose uptake is likely promoted by phenolic acids besides other bioactives. It can be hypothesized that consumption of nutraceutical‐rich extract of banana flower and pseudostem could replace some amount of insulin being taken for diabetes. Copyright © 2011 Society of Chemical Industry     

Physicochemical characteristics and sensory optimisation of pineapple leather snack as affected by glucose syrup and pectin concentrations

Effects of glucose syrup (2%, 4%, and 6%) and pectin (0.5%, 1.0%, and 1.5%) concentrations on physicochemical characteristics and sensory acceptability of machine‐formed pineapple leather snack were investigated. Changes in glucose syrup and pectin concentrations significantly affected velocity of forming and total soluble solids content of pineapple paste, but did not affect thickness of pineapple leathers. Increasing pectin concentrations generally increased redness (a*) and yellowness (b*), and hardness (tensile force and work) while decreased moisture content and a_w of pineapple leathers. Two most acceptable pineapple leathers were prepared with 6% glucose syrup and 0.5–1.0% pectin. Increasing pectin concentration from 1.0% to 1.5% negatively affected toughness acceptability, which was attributed to reduced moisture and a_w, and increased tensile force and work. The optimum formulation range consisted of 3.5–6.0% glucose syrup and 0.5–1.0% pectin, yielding products with acceptability scores of 6.7–7.3 (on a 9‐point hedonic scale) for appearance, sourness, sweetness, overall‐taste, toughness and overall‐liking.     

Determination of optimum harvest maturity and physico-chemical quality of Rastali banana (Musa AAB Rastali) during fruit ripening

BACKGROUND: A series of physico‐chemical quality (peel and pulp colours, pulp firmness, fruit pH, sugars and acids content, respiration rate and ethylene production) were conducted to study the optimum harvest periods (either week 11 or week 12 after emergence of the first hand) of Rastali banana (Musa AAB Rastali) based on the fruit quality during ripening. RESULT: Rastali banana fruit exhibited a climacteric rise with the peaks of both CO₂ and ethylene production occurring simultaneously at day 3 after ripening was initiated and declined at day 5 when fruits entered the senescence stage. De‐greening was observed in both of the harvesting weeks with peel turned from green to yellow, tissue softening, and fruits became more acidic and sweeter as ripening progressed. Sucrose, fructose and glucose were the main sugars found while malic, citric and succinic acids were the main organic acids found in the fruit. CONCLUSION: Rastali banana harvested at weeks 11 and 12 can be considered as commercial harvest period when the fruits have developed good organoleptic and quality attributes during ripening. However, Rastali banana fruit at more mature stage of harvest maturity taste slightly sweeter and softer with higher ethylene production which also means the fruits may undergo senescence faster than fruit harvested at week 11. Copyright © 2011 Society of Chemical Industry     

Lactose hydrolysis in acid whey with subsequent glucose isomerisation

The disposal of whey is a problem because of its high biological oxygen demand. Of the 1.8 × 10¹⁰ kg produced annually in the USA, only about half has any food or feed application (Jelen 1983). One possible approach to acid whey utilisation is the removal of the proteins either by ultrafiltration or by thermal precipitation, hydrolysis of lactose with soluble β-galactosidase (lactase, EC 3.2.1.23) and subsequent isomerisation of the glucose to fructose by the action of immobilised glucose isomerase (EC 5.3.1.5). The resulting syrup is composed of glucose, fructose and galactose plus small amounts of unhydrolysed lactose and other oligosaccharides. The syrup was found to have a predominantly sweet and slightly salty taste. Recently sucrose has been replaced in many foods by high fructose corn syrup produced by the action of glucose isomerase on glucose syrups from corn starch hydrolysates (Bucke 1981). The whey syrup also has potential as a sucrose substitute.     

Isolation,purification and characterisation of polygalacturonase from ripened banana (Musa acuminata cv. Kadali)

Bananas are the most important fruit crop in the world. Short shelf life of the fruit is the major limiting factor in international trade, and this is due to the softening of the pulp during ripening. Fruit softening is an important aspect of ripening process in fleshy fruits and is caused by the cumulative action of a group of cell wall‐modifying enzymes. Polygalacturonase (PG) is the key enzyme involved in the fruit softening process in banana, and this study reports the isolation, purification and characterisation of polygalacturonase enzyme from ripened fruits of a delayed ripened banana cultivar found specifically in Kerala (Musa acuminata cv. Kadali). PG was purified by ammonium sulphate fractionation followed by DEAE cellulose ion exchange chromatography and gel filtration using Sephadex G 100. The purified protein showed two subunits on SDS‐PAGE and a single band on native PAGE. Enzyme showed maximum activity at pH 3.5 and 40 °C. Fe³⁺ enhanced the activity more, while Mg²⁺ and Ca²⁺ slightly stimulated the activity of purified enzyme. Km value for substrate polygalacturonic acid was 0.06%.     

Apparent molar volumes and 1H-NMR relaxation values of glucose syrups

The apparent molar volumes and proton magnetic resonance ¹H-NMR pulse relaxation values of D-glucose and four commercial glucose syrups were determined in the concentration range 5–50% (w/w). The apparent molar volumes increased linearly with average degree of polymerisation (DP) of the syrups and were thus in excellent agreement with average molecular weight. These increases contrasted markedly with the known increases of specific rotation of maltooligosaccharides which reach a limiting value at about DP 7 or 8. Apparent specific volumes were all confined to the range 0.60–0.64 cm³g^?1 as expected for carbohydrates. They decreased sharply in the DP range 1–3 and showed little change thereafter. Apparent specific volumes also increased with increasing concentration of solute, as expected. Spin-spin relaxation values (T₂-values) decreased with increasing DP or increasing concentration of solute, as the proportion of ordered protons in solution increased. Consequently, within one glucose syrup, T₂ decreased with increasing apparent specific volume (increasing concentration) and, between glucose syrups, T₂ decreased with increasing DP. These results reflect the packing characteristics of the solutes among water molecules and accord with their known sweetness properties. They also underline the value of solution properties for the rapid characterisation of glucose syrups.     

Cultivation,preparation and consumption of ensete (ensete ventricosum) in Ethiopia

In Ethiopia almost 10 million people are dependent on ensete (Ensete ventricosum (Welw) Cheesrnan), also known as ‘false banana’. In the Gurage area in Central Ethiopia, agronomic and nutritional aspects of ensete were studied in 60 households in six villages. Ensete is propagated vegetatively and has a 6-year growing cycle during which it is transplanted three or four times. Men harvest the plants; women scrape the pseudo stem in order to separate the starchy pulp from the fibre, and pulverise the corm. The pulp is fermented and stored for up to 5–7 years in earthen pits. The yield of ensete food (ko'cho) was found to be 34 kg per plant or 9.5 tons ha ^?1 per year. Compared with other foods grown in Ethiopia, the energy yield of ensete (6.1 MJ m ^?2 per year) was higher than that of all cereals, Irish potato, sweet potato and banana, but lower than that of cassava. The protein yield of ensete was higher (11 ± 4gm^?2 per year) than all of the crops mentioned above, except for banana and Irish potato. To make ensete bread, fermented pulp is squeezed to make it drier, chopped to shorten the fibres and a 2 cm layer is baked for 15 min. Unfermented freshly harvested corm is also eaten after boiling. All foods have a low protein content (4–22 gkg^?1). Bu'lla, white desiccated juice collected from the pulp, is more energy rich (8.5 MJ kg^?1) than ko'cho (6.5 MJkg^?1). A dietary survey, conducted in 39 households comprising 237 persons, showed that the average daily intake of 0.55 kg ensete provided 68% of total energy intake, 20% of protein, 28% of iron but no vitamin A. Energy intake from all food consumed was very low, being only 60% of requirements, while protein intake at 107% was ample. Since ensete can be stored for years, is readily available throughout the year and can withstand dry periods, its cultivation can significantly improve household food security in highland areas prone to drought and famine.     

Production of isomalto‐oligosaccharide syrup from rice starch using an one‐step conversion method

Isomalto‐oligosaccharides (IMO) belong to a group of prebiotics that can significantly increase the number of protective gut microflora. A one‐step method using neopullulanase (NPN) in conjunction with saccharifying α‐amylase (SAA) for the bioconversion of rice starch into IMO was investigated. Purified rice starch slurry (30% w/w) was mixed with NPN (3.5 U g^?1 starch substrate) and SAA (6.5 U g^?1 starch substrate) and the slurry was incubated at 57 °C for 92 h under constant stirring. The carbohydrate composition of the resulting syrup was analysed by high performance liquid chromatography (HPLC) and the dextrose equivalent (DE) determined by titration. The amount of IMO in the syrup reached maximum (59.2%, dry basis) after 72 h of bioconversion. The concentration of glucose and maltose, which were the main carbohydrate residues of the IMO syrup, was 25.5% while the concentration of other oligosaccharide residues was about 1.0%. The results demonstrate that rice starch is a suitable matrix for producing IMO syrup and the one‐step conversion procedure appears to be an efficient method for converting starch into IMO syrup.     

Deacetylated chitin used as adsorbent in production of clarified pineapple syrup

A study of clarification of pineapple wastes syrup by a combined process of membrane ultrafiltration (UF), ion exchange and adsorption techniques using partially deacetylated chitin (PDC) as adsorbent material was conducted. Chitin from Black Tiger shrimp shell was used after undergoing deproteination, demineralisation and deacetylation with different concentrations of sodium hydroxide (NaOH). The performance of cation resin (Dowex 88), anion resin (Dowex 66) and PDC as adsorbent material were evaluated. Effects of flow rate ranging from 10 to 50 ml min⁻¹ on operation and regeneration of the resins were also investigated. Chitin yield was about 31·2% of the shrimp shells, corresponding to about 89% recovery of the total chitin content of the shells. When treated with 5%, 10%, 20% and 30% NaOH, the degree of deacetylation increased with increasing concentration of sodium hydroxide. In ion exchange process, cation resin removed more than 90% of K⁺, Mg²⁺ and Ca²⁺ from UF mill juice at a flow rate of 30 ml min⁻¹. In adsorption process, anion resin (Dowex 66) had more colorant removed (94% T) from UF mill juice than PDC treated with 30% NaOH (84·4% T). The optimum flow rate for cation resin was 10 ml min⁻¹ for both operation and regeneration while for PDC, 30 ml min⁻¹ was optimum for operation and 10 ml min⁻¹ for regeneration. The concentrated pineapple syrup was clear with a colour value of 70·2% and pH value of 4·96. The main reducing sugars after concentration were glucose, fructose and sucrose at 29·05, 15·72 and 18·62% (w/v), respectively. © 1998 SCI.