Banana Puree Research Articles

Change in aromatic components of banana during the preparation process of juice and microcapsule powder

SummaryBased on the importance of pleasant aroma on quality of banana products, a study was carried out on how the aromatic profile of banana is affected when fresh ripe banana is processed into puree, clear juice, microcapsulated banana powder and reconstituted juice. Solid‐phase micro‐extraction extraction and gas chromatography–mass spectrometry identification showed that puree, clear juice and reconstituted juice possessed the similar aromatic profiles with esters as the crucial components contributing the most to the characteristic aroma. Components of secondary importance to the aroma were contributed by the carbonyl fractions, followed by alcohols and hydrocarbons and elemicin. Only four compounds were retained on the surface of the microcapsulated banana powder. Primary component analysis extracted two principal components that exhibit 100% contribution to the total variance of the data set. Aroma profile of banana puree, clear banana juice and the reconstituted banana juice show no significant difference, with esters as the decisive components of the aroma and isoamyl butyrate as the major constituent of the esters, while the compounds responsible for the characteristic aroma were hardly detected from the microcapsulated banana powder, indicating that the main volatile components can be effectively encapsulated through microcapsulation.

Response surface methodology optimisation of immobilised Lactobacillus acidophilus banana puree fermentation

SummaryFermentation temperature (34–40 °C), total inoculum level (1%–3%, v/v) and peeled‐fruit‐to‐water ratio (12.5%–37.5%, w/v) were combined to study their effects on the fermentation of banana media by free and Ca‐alginate or κ‐carrageenan‐immobilised Lactobacillus acidophilus. A three‐variable and three‐level design method, analysed by response surface methodology (RSM), was used. These factors, except peeled‐fruit‐to‐water ratio, were found to be significantly effective on viable cell numbers and 1‐kestose (GF2) concentrations. Contour plots were generated using a graphing software package (Surfer Mapping System, Version 5.0; Golden Software Inc., Golden, CO, USA, 1994) based on fitted quadratic regression equations. Optimum conditions for the highest viable cell number and higher GF2 concentration were found to be around 35 °C fermentation temperature, 1.2% inoculum level and 25.0% peeled‐fruit‐to‐water ratio for Ca‐alginate immobilised cell fermentation, and around 39 °C fermentation temperature, 1.8% inoculum level and 25.0% peeled‐fruit‐to‐water ratio for κ‐carrageenan immobilised cell fermentation. For free cell fermentation, conditions for the highest viable cell number and higher GF2 concentration could not be obtained. The predicted optimum conditions of immobilised cell fermentation and the experimental values were consistent. This verified the adequacy of these predicted models. It was concluded that RSM was appropriate for the optimisation of banana puree fermentation using cell immobilised L. acidophilus, and products with better synbiotic effects could be obtained. The consumer palatability of the immobilised cell‐fermented banana puree was found to be acceptable.

An investigation of some properties of banana yogurts made with commercial ABT‐2 starter culture during storage

Five yogurt batches were prepared with banana puree and sugar combinations and ABT‐2 (Streptococcus salivarius ssp. thermophilus, Lactobaccilus acidophilus and Bifidobacterium spp.) as starter culture. The addition of fruit influenced (P < 0.05) the syneresis, titratable acidity and pH, whereas the viscosity value, and S. salivarius ssp. thermophilus, L. acidophilus and Bifidobacterium spp. counts were found to be insignificant. Storage time significantly (P < 0.05) affected the syneresis, titratable acidity, pH value, and S. salivarius ssp. thermophilus counts, while the viscosity value and L. acidophilus and Bifidobacterium spp. counts were not affected. The sensory evaluations showed that the sample B was most preferred by panellists.

Pineapple Juice and Its Fractions in Enzymatic Browning Inhibition of Banana [Musa(AAA Group) Gros Michel

The effectiveness of pineapple juice in enzymatic browning inhibition was evaluated on the cut surface of banana slices. After storage of banana slices at 15 degrees C for 3 days, pineapple juice showed browning inhibition to a similar extent as 8 mM ascorbic acid but less than 4 mM sodium metabisulfite. Fractionation of pineapple juice by a solid-phase C18 cartridge revealed that the directly eluted fraction (DE fraction) inhibited banana polyphenol oxidase (PPO) about 100% when compared to the control. The DE fraction also showed more inhibitory effect than 8 mM ascorbic acid in enzymatic browning inhibition of banana puree during storage at 5 degrees C for 24 h. Further identification of the DE fraction by fractionation with ion exchange chromatography and confirmation using model systems indicated that malic acid and citric acid play an important role in the enzymatic browning inhibition of banana PPO.

Influence of dehydration-rehydration process on rheological properties of liquid fruit foods

The effects of the dehydration-rehydration process on the recovering of the original rheological characteristics of the re-hydrating solution were studied. Four different fruit fluid products were investigated: apricot, banana purees, non-pureed citrus fruits, i.e mandarin juice and lemon treacle, respectively. The static rheological behavior of both pureed and non-pureed products was measured for the raw material, i.e. before the drying process, and after the rehydration procedure. First of all, the results show that rehydrated materials have different rheological behaviors from fresh ones, especially in the case of starch added non-pureed products. Such differences can be due to both the stress conditions induced by mechanical drying and successive rehydration or to other factors such as, for example, the starch addition. These results were relevant to quantify the rehydration efficacy of pureed and non-pureed foods, suggesting than more than just one parameter should be controlled for liquid foods when the rehydration procedure is carried out.

Comparison of volatiles of banana powder dehydrated by vacuum belt drying, freeze-drying and air-drying

Banana puree was dehydrated by using three different drying methods: vacuum belt drying (VBD), freeze-drying (FD) and air-drying (AD) to produce banana powder. Volatiles were extracted from dried banana powder with solid phase micro-extraction (SPME), and separated and identified by gas chromatography–mass spectrometry (GC–MS). SAS (statistical analysis system) was used to evaluate the contribution of the main volatiles. Esters play the most important role in banana powder aroma. The main components detected in banana powder which are responsible for its fruity odor were 3-methylbutanoic acid 3-methylbutyl ester, 3-methylbutyl acetate and butanoic acid 3-methylbutyl ester. Most of the alcohols identified in banana powder were enols and some were of the long chain type. Eugenol and elemicin which give the product its typical mellow aromas were also identified. Alkyls, alkene and alkyne constituted the minor components in banana powder. Basing on the principal component analysis of statistical analysis system, it can be inferred that the preferred method for producing banana powder with the optimum aroma is FD, followed by VBD and then AD.

Heat transfer during thermal processing of a temperature dependent non-Newtonian fluid in a tubular heat exchanger

Heat transfer is highly dependent upon fluid properties and operating conditions for a particular heat exchanger. Determination of heat transfer coefficients in aseptic processing of a temperature dependent non-Newtonian fluid (banana puree) as a function of steam temperature, flow rate and heat exchanger's length/diameter ratio is essential for modeling the thermal process. A commercial acidified aseptic banana puree with an average pH of 4.49 and average soluble solids concentration of 22.1 °Brix was processed in a tubular heat exchanger with two heating sections. Three flow rates (2.5 × 10 −5, 3.7 × 10 −5 and 4.7 × 10 −5 m 3 s −1), three steam temperatures (110.0, 121.1 and 132.2 °C) and two length ( L)/diameter ( D) ratios (250 and 500) were studied. Density, thermal conductivity and specific heat capacity were considered constant and heat transfer coefficients were calculated from the temperature data obtained. For an L/ D ratio of 500, heat transfer coefficients varied from 654.8 to 842.2 W m −2 K −1, while for an L/ D ratio of 250 heat transfer coefficients varied from 735.5 to 1070.4 W m −2 K −1. An empirical correlation was proposed and verified, which explained the experimental data within 10% error.

Velocity and temperature profiles, heat transfer coefficients and residence time distribution of a temperature dependent Herschel–Bulkley fluid in a tubular heat exchanger

Banana puree was studied as a temperature dependent Herschel–Bulkley fluid. Experiments were conducted in a tubular heat exchanger at three flow rates (2.5 × 10 −5, 3.7 × 10 −5 and 4.7 × 10 −5 m 3 s −1), at three steam temperatures (110.0, 121.1 and 132.2 °C) and two length/diameter ratios (250 and 500). The minimum, maximum and average residence times were calculated from on-line electrical conductivity measurements. Inlet and outlet temperatures were recorded. A model was proposed to obtain heat transfer coefficients and velocity and temperature profiles in the heat exchanger. The continuity, energy and momentum equations were integrated using a finite difference method. The heat transfer coefficients varied from 654.8 to 1070.4 W m −2 K −1 for average velocities of 0.24–0.40 m s −1. There is good agreement between experimental parameters and those predicted by the model.

Rheological Properties of Banana Puree at High Temperatures

The rheological behavior of banana puree was determined using a dynamic stress rheometer with a pressure couette fixture, which allowed experiments to be conducted at high temperature. The pressure couette was pressurized with compressed air to 206.8 kPa (gage pressure) and experiments were carried out at temperatures ranging from 30 to 120°C. The shear stress values ranged from 10 to 170 Pa and the shear rate values from 10−5 to 103 s−1. The model that best fitted the experimental data at all temperatures was the Herschel-Bulkley model. There was a usual tendency for the apparent viscosity to decrease with increasing temperature but an increase in apparent viscosity with increasing from 50 to 60°C and from 110 to 120°C was found. This could be due to interaction of polysaccharides present in banana puree. There was a slight difference between the apparent viscosity values for increasing shear stress sweeps and those for the decreasing shear stress sweeps suggesting time dependency of the rheological behavior. Models were proposed to correlate the parameters of the Herschel-Bulkley model and viscosity with temperature.

Foaming and drying behaviour of ripe bananas

The foaming of ripe bananas and the forced air-drying characteristics of the resulting banana foam mats were studied. Fresh banana puree with a density of 0.93 g/ml was foamed to a density of 0.50 g/ml after 12 min of whipping by the addition of 10 g/100 g soy protein as a foam inducer. Glyceryl monostearate did not induce foaming while commercially available food ingredients, Dream Whip and Gelatine induced foaming but such foams were not suitable for subsequent drying. Banana foam mats were dried at temperatures from 45°C to 90°C in a forced air, cabinet dryer, to a hard, porous and brittle solid which was amenable to grinding so as to produce a dehydrated banana powder. The transient drying behaviour of such mats was described by a capillary model of the form ln( M/ M 0)=− Kt and over the bulk of the moisture ratio range, 0.05⩽ M/ M 0⩽1.0. The drying time ( t) was directly related to the thickness of the foam mats. K values increased from 0.248 to 0.809 h −1 as the drying air temperature was raised from 45°C to 90°C. Increasing the air velocity from 0.62 to 1.03 m/s did not profoundly influence the drying rate.

Survival of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella in Juice Concentrates

The survival of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella was studied in apple, orange, pineapple, and white grape juice concentrates and banana puree. Pouches of juice concentrate or puree were inoculated with pathogens at a level ≥103 CFU/g and stored at −23°C (−10°F). Pathogen survival was monitored at 6 and 24 h, once a week for four consecutive weeks, and biweekly thereafter until 12 weeks. When pathogens were not detectable by direct plating, samples were enriched in universal preenrichment broth for 72 h and plated on selective media. Results showed that E. coli O157:H7, L. monocytogenes, and Salmonella were recoverable from all five concentrates through 12 weeks of storage at −23°C.

Effect of food-processing on the degradation of fructooligosaccharides in fruit

The effect of process on fructooligosaccharide degradation in stewed apple-banana and three apple dessert was studied. 1-Kestose was analysed using an accurate analytical method for carbohydrate determination (high-performance anion exchange chromatography with pulsed amperometric detection, HPAEC–PAD). It appears that the content of 1-kestose in raw material was much higher than in the finished product. Furthermore, a banana puree incubated for 30 min over a temperature range (80–110 °C), supposed to favour degradation, appeared stable. This indicate that its the formulation rather than cooking or pasteurization which is responsible for the fructooligosaccharide loss.

Banana puree fermentation by Lactobacillus acidophilus immobilized in Ca-alginate.

Banana puree fermentation by Lactobacillus acidophilus immobilized in Ca-alginate.

Influence of storage on the physicochemical, microbiological and sensory properties of heat and chemically treated melon-banana beverage

Melon seed milk and banana puree supernatant were prepared from melon (Colocynthis citrullus) seed and banana (Musa sapientum) fruit, respectively. Banana puree supernatant (16%, v/v) was used to replace melon seed milk to obtain a melon-banana beverage. Some portions of the beverage were processed at 85 °C, 100 °C and 121 °C for 15 min, respectively while others were treated with citric acid, sodium benzoate and sodium benzoate with pasteurization (85 °C, 15 min). Physicochemical, nicrobiological and sensory changes in the beverages stored at 30 ± 2 °C for 50 days were determined. Acceptability of the melonbanana beverage was not adversely affected by the process conditions employed. No microbial growth was observed in beverages treated with sodium benzoate, and sodium benzoate with pasteurization. Plate counts on 121 °C−15 min treated beverages were less than 50 cfu/ml during the 50 days storage period. Vitamin C, soluble solids, titratable acidity and pH of beverages treated with sodium benzoate, and sodium benzoate with pasteurization showed no significant changes (p > 0.05) with storage. A combination of sodium benzoate and heat treatment maintained acceptability of the beverage for 35 days. The 121 °C−15 min treated beverage remained acceptable up to 12 days.

Density of banana puree as a function of soluble solids concentration and temperature

Density of banana puree was determined in a concentration range from 10 to 80 oBrix and temperatures between 5 and 80 °C. Density values were found to increase with the increase of soluble solids concentration and the decrease of temperature. The results were analyzed to obtain this property as a function of temperature and soluble solids concentration and an equation, statistically significant at a confidence level of 99%, was proposed. For each different concentration, density variation with temperature was found to follow an Arrhenius-type relationship, with activation energy values between 748.36 and 1137.36 J/g-mol and all equations were statistically significant at a confidence level of 99%. A relationship between soluble solids concentration and activation energy was also obtained.

Polyphenoloxidase Activity and Color of Blanched and High Hydrostatic Pressure Treated Banana Puree

ABSTRACTThe effects of blanching and high hydrostatic pressure (HHP) treatments on natural flora evolution, polyphenoloxidase (PPO) activity and color of banana puree adjusted to pH 3.4 and water activity (aw) of 0.97 were evaluated during 15 days storage at 25°C. Standard plate as well as yeast and mold counts of HHP treated purees were <10 CFU/g throughout storage. Blanching time was found to affect (P<0.05) puree color. HHP treatments retained the initial color of the banana purees. Longer browning induction times and slower browning rates were observed when a longer blanching time was combined with a 689 MPa pressure treatment. A residual PPO activity < 5% was observed in the puree when a 7 min blanch was followed by HHP treatment at 689 MPa for 10 min.

Processamento térmico de purê de banana (Musa cavendishii, Lamb.) em embalagens flexíveis esterilizáveis

O objetivo deste trabalho foi estabelecer as condições de processo térmico de purê de banana, variedade "nanica", em bolsas esterilizáveis porção individual (130 x 170mm). Os frutos foram selecionados, aquecidos a 98°C/5min. para inativação enzimática, separadas as sementes e fibras num despolpador com malha de 0,08cm de diâmetro e depois o purê foi embalado nas bolsas sob um vácuo de 25mmHg, resultando em média 2,7ml de ar residual por bolsa. Em seguida as bolsas foram processadas sem agitação e em posição horizontal numa autoclave horizontal, a 115°C/158KPa, com imersão total de água quente. O tempo de manutenção do processo foi de 7,5min. Inicialmente foi utilizado o Clostridium butyricum como microrganismo alvo do processo, entretanto, observou-se que esta bactéria apresentara uma resistência térmica em purê de banana (pH 4,6) um pouco menor que o valor estimado para o Clostridium botulinum, D115=0,183min. e D115=0,236min respectivamente, sendo assim, o C. botulinum foi escolhido como microrganismo alvo da esterilização do produto. O valor de F121,1°C aplicado foi de 0,64min. para causar 12 reduções decimais, calculado segundo PFLUG (1985) para um pH de 4,6, e verificado pelo método geral. Este valor somente foi considerado para a fase de aquecimento, deixando a letalidade do resfriamento (0,34min.), que foi realizada com água à temperatura ambiente, como segurança de processo. Nos testes de penetração de calor foram encontrados os valores médio de fh=6,8min; jh=0,48; fc=17,4min. e jc=1,3 demonstrando assim, que o produto é altamente condutivo. Nenhuma alteração no produto nem nas embalagens foi notada após a aplicação do ensaio de esterilidade comercial em 36 bolsas processadas contendo purê de banana, confirmando assim, a eficácia do tratamento térmico aplicado.

USING BROOKFIELD DATA AND THE MITSCHKA METHOD TO EVALUATE POWER LAW FOODS

ABSTRACTMitschka proposed a simple technique to calculate average shear stress and average shear rate from data obtained with Brookfield viscometers. It allows for estimation of the apparent viscosity, the flow behavior index, and the consistency coefficient of power law fluids. This method was evaluated for typical shearthinning foods (banana puree, salad dressing, enchilada sauce, and pancake syrup) and found to have excellent potential for quality control testing in the food industry. Results compared favorably with those obtained with a standard cone and plate viscometer.

Evaluation of in-line sensors for selected properties measurements in continuous food processing

The present investigation deals with the evaluation of five in-line sensors — refractometer, viscometer, density meter, pH meter and power meter — to measure soluble solids, viscosity, density, pH and power respectively in the continuous processing of different food products. The food products used were: apple sauce, banana puree, banana concentrate and a yogurt beverage. The food products were processed in a pilot scale setup consisting of feed tank, pumps, in-line sensors, data logger and other accessories. The variables covered in the present investigation were: temperature (10–60 °C), flow rate (18.92–113.56 l/min) and soluble solids or Brix (5–30%, w/w). These sensors were calibrated off-line by an Abbe refractometer (for soluble solids), pycnometer (for density) and pH meter (for pH). Off-line measurements were also taken for viscosity by Brookfield viscometer and Bostwick viscometer. Total solids were measured by a modified vacuum oven method. An in-line Maselli refractometer gave values of soluble solids within an accuracy of ±0.5%. The in-line density meter gave consistently higher values by about 4%. In-line viscosity values could not be compared with the off-line measurements because of the order of magnitude difference in the shear rate during stationary and flow conditions of the food products. pH values obtained by the in-line sensor were very close to the off-line values (maximum deviation: ±1%). Power values could not be compared, since there was no method available to measure it off-line. The sensors gave satisfactory results under different operating conditions in the range of variables mentioned. Their performance was not affected by prolonged use during continuous operations of about 8 h.

HPLC determination of thiol-containing anti-browning additives in fruit and vegetable products

The HPLC determination of residual thiol-containing anti-browning additives (cysteine, N-acetyl-cysteine and reduced glutathione) in treated fruit and vegetable products using the Ellman's reagent (5,5′-dithiobis(2-nitrobenzoic acid); DTNB) is described. The thiols were isolated by extraction with solvent containing NaF, EDTA, acetic and ascorbic acids and derivatized with the Ellman's reagent in an aqueous medium at pH 8.0. The resulting disulphides were determined by reverse phase HPLC with mobile phase consisting of methanol and phosphate buffer pH 7.5. The UV-detection at 330 nm was used. The optimal extraction and derivatization conditions were found and the method was used to determine the residual concentrations of thiols in potato, avocado, apple and banana purees, sliced mushrooms and frozen basil treated with cysteine.