Rheological and functional properties of flours from banana pulp and peel

Unripe banana flour can be an alternative to minimize post‐harvest loss and to increase the aggregate value of banana fruit. Flour from unripe banana is rich in phytosterols and resistant starch, being proposed as health food. Flours from unripe banana peel and pulp were evaluated on their composition, phytosterols content, thermal and rheological properties, and pasting profiles. High amounts of β‐sitosterol, campesterol, and stigmasterol were found in flour from banana peel. These samples showed lower viscosity values of pasting profiles, lower energy enthalpy on gelatinization, and higher temperature of gelatinization than those ones from pulp. Anti‐oxidant treatment of fruits with citric acid does not change pasting profiles of flours from pulp, but resulted in slight increase in viscosity, suggesting that structure of starch could be modified by acidification.     

Physicochemical properties,resistant starch content and enzymatic digestibility of unripe banana,edible canna,taro flours and their rice noodle products

Unripe banana, edible canna and taro flours, which have been reported to contain significant amounts of fibre, were investigated for their physicochemical properties, resistant starch (RS) content and in vitro starch digestibility, and compared with commercial high‐fibre‐modified starches from corn and tapioca. Differential scanning calorimetry showed a single endothermic peak located around 70–83 °C for the samples except the modified starches, which exhibited no transition enthalpy. The samples showed different pasting behaviours in the Rapid Visco‐Analyser (RVA) ranging from full to restricted swelling. The RS content varied from 1–26 g per 100 g dry sample, and the estimated glycaemic indices (GIs) of the samples were from 67% to 99%. Generally, samples with high RS were low in GI values. The starches produced acceptable rice noodles but with reduced rate of starch digestion and GI. The effects of the unripe banana, edible canna and taro flours on starch digestibility were either comparable or better than the commercial modified starches. These flours can substitute commercial modified starches to lower GIs of noodles and identical foods.     

In-vitro digestibility,textural and quality characteristics of ditalini pasta fortified with green banana flour and its type -IV modified starch

Resistant starch in unripe banana offers a possibility to alter the glycemic properties in convenience foods, such as pasta. In this study, pasta formulations were tried by replacing 30% semolina with varying proportions of green banana flour (GBF) and banana-modified starch (MS). The effect of substitution on physicochemical and functional properties, including in-vitro starch digestibility, antioxidant property and consumer acceptability, was evaluated. Among the composite flours, MS recorded higher swelling power and water holding capacity. The replacement of semolina with GBF resulted in higher resistant starch, 4–5 times enhanced indigestible fraction, phenols, flavonoids and antioxidant activity in pasta. Pronounced increment was also observed in potassium, calcium and magnesium content in blended pasta. Optimal cooking time was reduced with the addition of GBF, whereas it was enhanced with MS. GBF and MS in the blends, decreased the hydrolysis rate (up to 24%) and glycemic index (up to 17%) of pasta. However, the addition of MS beyond 10% negatively influenced springiness and chewiness. Microstructural studies explained the positive structural changes with the addition of GBF and MS. Sensory attributes disclosed that the addition of 25% GBF and 5% MS is a desirable proportion for pasta with a functional characteristics.     

Effects of osmo-dehydration,blanching and semi-ripening on the viscoelastic,water activity and colorimetry properties of flour from three cultivars of plantain (Musa AAB)

The viscoelastic properties, water activity and colorimetry measurements of plantain flour produced by hot-air dehydration of three cultivars, French Horn, False Horn and True Horn local plantains were studied. Treatments given to the plantains before the hot-air dehydration were osmo-dehydration, hot-water blanching and semi-ripening and fresh unripe. The best pasting characteristics occurred for True Horn local and False Horn osmo-dehydrated flours. Water activity and moisture content were 0.27–0.39 a_w and 5.08–7.25%, respectively with the lowest recorded for False Horn osmo-dehydrated flour. Colour parameters were in the range of 87.34–79.56 and 15.71–26.74 for L? and b?, respectively. The least browning colour (a?) was exhibited by True Horn local and False Horn osmo-dehydrated flours. Statistical significances (P < 0.05) were recorded for water activity, moisture content and a? colour parameter between process treatments for fresh unripe, semi-ripe, osmo-dehydration and blanching whereas no statistically significances occurred for varietal differences for False Horn, True Horn local and French Horn plantains. However, the viscoelastic properties were significant for F-ratios at P > 0.05. Process treatments of osmo-dehydration, blanching and semi-ripening contribute significantly to the differences for water activity, moisture content, browning effect and viscoelastic properties compared to plantain varieties, with osmo-dehydration emerging as the best treatment method.Industrial relevanceThis work is a representation of peculiar differences for water activity, moisture content, non-enzymatic browning effect and viscoelastic properties among process treatments of osmo-dehydration, blanching, semi-ripening and fresh unripe. Important results were obtained for the flour industries for decisions on selecting osmo-dehydration among the process treatments for plantain (Musa AAB) flour in order to take advantage of the consumer demand for plantain flour.     

A study of the effect of the drying process on the composition and physicochemical properties of flours obtained from durian fruits of two ripening stages

Durian cv. Monthong with two ripening stages (unripe and fully ripe) was subjected to microwave vacuum drying (MWD) at 5.49 W g^?1 and hot air drying (HAD) at 60 °C. With an increase in ripening degree, the starch content was significantly (P ≤ 0.05) decreased from 40.08–40.42% to 9.44–11.76%. X‐ray diffraction indicated that the crystalline pattern was changed from starch to sucrose. The starch granule morphology of durian flour was conserved for both drying conditions. Peak gelatinisation temperatures of MWD and HAD flours were increased significantly (P ≤ 0.05) from 56.71–57.32 to 60.71–61.23 °C. Using different drying methods, MWD flour had less a*‐value (P ≤ 0.05) than HAD flour. The peak viscosity and trough of the HAD unripe durian flour (5.92 RVU and 3.45 RVU, respectively) were significantly (P ≤ 0.05) lower than those of the MWD unripe durian flour (34.32 RVU and 11.57 RVU, respectively).     

Nixtamalised flour and tortillas from transgenic maize (Zea mays L.) expressing amarantin: Technological and nutritional properties

Nixtamalised flour from transgenic maize (genetically modified maize with the cDNA of amarantin) and its tortillas were evaluated for some technological and nutritional properties and compared to the commercial brand MASECA^™. Nixtamalised transgenic maize flour (NTMF) showed higher protein content, total colour difference, pH, water solubility index, essential amino acids content and lower Hunter “L” value, water absorption index, resistant starch and retrograded resistant starch than MASECA^™ flour. Tortillas from NTMF had higher protein content (12.64% vs 8.93%, db), essential amino acids content and calculated protein efficiency ratio (C-PER; 2.05 vs 1.04) than tortillas from MASECA^™. Tortillas from both nixtamalised transgenic maize and MASECA^™ flours showed similar sensory properties (puffing and acceptability). The use of transgenic maize for flour and tortilla preparation may have a positive impact on the nutritional status of people from countries where maize is the basic staple food.     

Effects of rice properties and emulsifiers on the quality of rice pasta

Two commercial rice flours (GTIndica and GTJaponica, with amylose contents of 306.8 and 185.2 g kg^?1 respectively) and their blended flours were used to make rice pasta. The effects of two emulsifiers (distilled glyceryl monostearate (GMS) and a commercial emulsifier (KM3000)) on the pasting and thermal properties of dried rice pasta were investigated using a Rapid Visco Analyser (RVA) and a differential scanning calorimeter (DSC). The rice pasta made from high‐amylose rice flour had better extrusion properties, better texture, whiter colour, less cooking loss and better eating quality than that made from low‐amylose rice flour. The maximum amount of low‐amylose rice flour that could be blended in for making an acceptable quality of rice pasta was 500 g kg^?1. A soft texture, low adhesiveness and low gumminess of cooked rice pasta were obtained by adding 10 g kg^?1 GMS. SEM investigations showed that use of an emulsifier restricted the swelling of starch granules, especially for the pasta made from high‐amylose rice flour. © 2001 Society of Chemical Industry     

Molecular and physicochemical characterisation of starches from yam,cocoyam, cassava,sweet potato and ginger produced in the Ivory Coast

Granule sizes, macromolecular features and thermal and pasting properties of starches from seven tropical sources (Florido, Kponan and Esculenta yams, cocoyam, cassava, sweet potato and ginger) were compared with those of several well‐known cereal, legume and tuber starches. The aim of the study was to characterise some non‐conventional starches with a view to possibly marketing them. Amylose content varied from 148 mg g^?1 in Esculenta starch to 354 mg g^?1 in smooth pea starch. For total starches, weight‐average molar mass (M?_w) ranged between 0.94 × 10⁸ and 1.80 × 10⁸ g mol^?1 for potato and normal maize starches respectively. Gyration radius (R?_G) varied from 157 nm for ginger starch to 209 nm for normal maize starch. Gelatinisation enthalpy (ΔH) ranged between 9.8 and 20.7 J g^?1 for wheat and Florido starches respectively. Gelatinisation peak temperature (T_g) varied from 58.1 °C for wheat starch to 87.3 °C for ginger starch. Native starch granule mean diameter ranged between 5.1 and 44.5 µm for Esculenta and potato starches respectively. Cassava and potato starches had the highest swelling power and dispersed volume fraction at all treatment temperatures, while ginger starch had the lowest. Cocoyam starch had the highest and ginger starch the lowest solubility at 85 and 95 °C. Cassava starch was the most stable under cold storage conditions. Roots and tubers such as ginger and cassava produced in the Ivory Coast are new sources of starches with very interesting properties. Thus these starches could be isolated on an industrial level in order to market them. Copyright © 2007 Society of Chemical Industry     

Physicochemical Characteristics of Starches from Unripe Fruits of Mango and Banana

Mango and banana starches were isolated from unripe fruits and their morphology; thermal and pasting properties; molar mass and chain length distribution were determined. Mango starch granules were spherical or dome‐shaped and split, while banana starch had elongated granules with a lenticular shape. Amylopectin of both fruit starches had a lower molar mass than maize starch amylopectin; however, mango amylopectin had the highest gyration radius. Banana amylopectin showed the lowest percentage of short chains [degree of polymerization (DP) 6–12] and the highest level of long chains (DP ≥ 37); mango amylopectin presented the highest fraction of short chains, but the level of longest chains was intermediate between those of banana and maize amylopectins. Banana starch presented the highest average gelatinization temperature followed by mango starch and maize starch had the lowest value; a similar pattern was found for the gelatinization enthalpy. The two fruit starches had a lower pasting temperature than maize starch, but the former samples showed higher peak and final viscosities than maize starch. Structural differences identified in the fruit starches explain their physicochemical characteristics such as thermal and pasting behavior.     

Influence of the Heating Rate on the Pasting Properties of Various Flours

Viscoamylographic tests were carried out on six commercial flour samples, three wheat flours (WF), two semolinas (S) and one rice flour (RF), using the Brabender Micro Visco‐Amylo‐Graph (MVA). The slurries were subjected to a definite temperature profile (30°C‐95°C, 95°C×30 min, 95°C‐50°C, 50°C×30 min), stirring at 250 min⁻¹ and using a 300 cm·g_f cartridge and recording the viscosity (in Brabender Units, BU) as a function of temperature and time. The aim of this work was to evaluate the influence of different heating rates (1.5, 3.0, 5.0, 7.5, 10.0°C/min) on the pasting properties of the various flours. The peak viscosity of WFs and Ss increased when high heating rates were applied, while the RF showed similar pasting properties independently of the heating rate. These behaviours were mainly ascribed to the different molecular organisation of the starch granules, responsible of different swelling and gelatinising extents, and also to a different kinetic of alpha‐amylase inactivation according to the heating rate applied. The key role of the alpha‐amylase activity in controlling the pasting viscosity of the different samples was demonstrated by the viscoamylographic test performed in the presence of silver nitrate as enzyme inhibitor.     

Effect of solvents and supercritical-CO2 extraction of lipids on physico-chemical,functional, pasting and rheological properties of hard,medium hard and soft wheat varieties

This study was conducted to compare the effect of lipids removal using supercrital-CO₂ extraction and organic solvents (hexane and isopropanol) from hard and soft wheat flour varieties. Flours were evaluated for physicochemical properties (protein, ash, hunter colour), sodium dodecyl sulphate-polyacrylamide gel electrophoresis, foaming properties, water and oil absorption capacity, pasting, farinographic and dynamic rheology. Protein content of flours increased after defatting and supercritical fluid extracted (SCE) wheat flours showed the highest increase. SCE flours showed higher peak viscosity than native and hexane extracted (HE) and isopropyl alcohol extracted (IPAE) flours. Functional properties improved upon defatting and the highest increase in functional properties was observed for SCE flours. Empirical and fundamental rheological measurements were affected by defatting and SCE flours showed the highest change in visco-elasticity. SC-CO2 was proved better alternative technique over conventional organic solvent methods to remove lipids from flours that brought desirable changes in some functional properties.     

Synergism between lipoxygenase‐active soybean flour and ascorbic acid on rheological and sensory properties of wheat bread

BACKGROUND: The interaction between lipoxygenase‐active soybean flour (LOX) and ascorbic acid (AA), on colour, rheological and sensory properties of wheat bread was studied with the aim of reducing the applied quantity of additives in bread formulations. RESULTS: The ascorbic acid (0–500 ppm) and active soybean flour (0–1%) mixture improved bread‐crumb colour by lowering the yellow hue in a higher proportion than those expressed by the components alone, characterising a synergistic mechanism (?_b = 15.1? (1.7 × LOX) ? (0.5 × AA) ? (5.8 × LOX × AA), where ?_b represent the estimated value for the yellow hue parameter). No differences in flavour and porosity were seen between the samples. As supported by the instrumental methods, breads made with active soybean flour and ascorbic acid (LOX + AA) had whiter crumbs and were softer and springier than controls as assessed by a trained sensory panel. In summary, the combination of both active soybean flour and ascorbic acid showed synergism, promoting a greater bleaching effect than when used alone. CONCLUSION: These results suggest the potential use of active soybean flour as a synergistic ingredient in the substitution of artificial additives in bread making. Since the interaction on the bleaching response was not linear and active soybean flour showed a higher iron concentration (66.40 ± 4.23 µg g^?1) than non‐active soybean flour (52.30 ± 0.40 µg g^?1), more studies are warranted to establish the biochemical mechanisms involved in this interaction. Copyright © 2007 Society of Chemical Industry     

Effect of irradiation,with and without cooking of maize and kidney bean flours,on porridge viscosity and in vitro starch digestibility

African traditional weaning foods are usually prepared from starchy flours at a total solids content of 50–100 g l^?1, giving a viscosity of 1000–3000 cP which is consumable by infants. These porridges have very low energy and nutrient densities. Processing to reduce the porridge viscosity and improve the energy and nutrient density may help in solving this problem. Maize, kidney bean and their 70:30 composite flours were irradiated at 0–10 kGy at room temperature. Irradiation greatly reduced the viscosity of porridges, probably by starch depolymerisation. Irradiation improved the starch digestibility of raw bean flours, possibly either by inhibiting α‐amylase inhibitors or by weakening the thick cell walls that enclose the starch granules, thus improving accessibility to enzymes. However, in raw maize, cooked maize and cooked bean flours there was maximum starch digestibility at a dose of 2.5 kGy, followed by small but significant decreases in starch digestibility at higher doses, more so in maize than in bean flours. The decrease in digestibility could be due to the formation of inhibitors of amylolytic enzymes (Maillard reactions products) or to the formation of resistant starch. Irradiation doses required to increase the total solids content of traditional maize‐ and/or bean‐based weaning porridges to at least 200 g l^?1 do not compromise starch digestibility significantly. © 2001 Society of Chemical Industry     

In vitro starch digestibility,expected glycemic index,and thermal and pasting properties of flours from pea,lentil and chickpea cultivars

In vitro starch digestibility, expected glycemic index (eGI), and thermal and pasting properties of flours from pea, lentil and chickpea grown in Canada under identical environmental conditions were investigated. The protein content and gelatinization transition temperatures of lentil flour were higher than those of pea and chickpea flours. Chickpea flour showed a lower amylose content (10.8–13.5%) but higher free lipid content (6.5–7.1%) and amylose–lipid complex melting enthalpy (0.7–0.8 J/g). Significant differences among cultivars within the same species were observed with respect to swelling power, gelatinization properties, pasting properties and in vitro starch digestibility, especially chickpea flour from desi (Myles) and kabuli type (FLIP 97-101C and 97-Indian2-11). Lentil flour was hydrolyzed more slowly and to a lesser extent than pea and chickpea flours. The amount of slowly digestible starch (SDS) in chickpea flour was the highest among the pulse flours, but the resistant starch (RS) content was the lowest. The eGI of lentil flour was the lowest among the pulse flours.     

Effect of processing and storage time on in vitro digestibility and resistant starch content of two bean (Phaseolus vulgaris L) varieties

Seeds from two commercial bean varieties were cooked and stored for different times and analysed for chemical composition and in vitro starch digestibility. Parallel portions of cooked seeds were dried at 55 °C, milled and stored as flours. In general, protein and ash contents in both samples did not change with storage time, but statistical differences were shown between the two varieties (p < 0.05). Available starch (AS) contents in flours from the ‘negro’ variety did not change (p < 0.05) with storage time and, in general, were higher than in ‘flor de mayo’ samples, whose AS levels decreased during storage. The lower AS in ‘flor de mayo’ flour could be the consequence of formation of resistant starch due to retrogradation. Samples of whole ‘negro’ seeds did not show differences in AS content at 0, 24 and 48 h of storage compared with the corresponding flours, but at 72 and 96 h the AS increased in the whole samples. ‘Flor de mayo’ showed a similar pattern in flour and whole samples, with slightly higher values in the whole seeds. In general, total resistant starch (RS) content in the two varieties was higher in the flours than in ‘whole’ seeds, a fact that is not easy to explain at present. ‘Negro’ flour presented an RS content around 65.0 g kg^?1, and approximately 55.0 g kg^?1 was recorded in ‘flor de mayo’, with slight changes when storage time increased. Whole ‘flor de mayo’ showed significant levels of the retrograded portion of resistant starch (RRS), which did not change with storage time (p < 0.05). However, values were lower than in the flours. A pattern similar to that of the ‘negro’ variety was obtained for ‘flor de mayo’, since the flour exhibited higher amounts of RRS; however, in this variety, the RRS content in ‘whole’ samples decreased after prolonged storage. Flours presented higher amylolysis rates than whole samples, and the ease of digestion increased with storage time. Copyright © 2003 Society of Chemical Industry     

Wheat batter physical properties as influenced by starch/flour types and egg contents

Batter liquid–solid phase interactions can play a critical role in determining the functionality, including adherence, appearance and texture of end use coated product. Batter chemical composition is a key factor affecting batter characteristics. The effect of substituting wheat flour with fractions of rice flour, native corn starch, modified waxy corn starch, tapioca starch and lupine flour ranging from 26 to 56% of the solid phase and egg levels ranging from 6 to 35% of the liquid phase on the rheological properties of batter systems was studied. Results indicated that lupine flour had the greatest water holding capacity (WHC) ranging from 93.9 to 119.3% of various lupine flour percent to egg levels used. Flow behaviour index of batter flour treatments ranged from 0.91 to 1.87; values that were significantly (P?<?0.05) greater than a 100% control wheat flour. Consistency coefficient of treatments ranged from 0.01 to 0.37 mPa sⁿ; values that were significantly lower than wheat flour (i.e., 5 mPa sⁿ). Egg level used in this study had minimal effect on treatment rheological properties. The changes in WHC and viscoelastic properties of treatments were attributed to changes in protein and fibre contents and structure as a result of replacing wheat flour with starch/flour. Protein–starch–lipid matrix formation and variation in water absorption kinetics of treatments most probably wrought batter functionality. The increase in pasting properties with the increase in starch/flour contribution suggested an increased contribution of starch in forming a net effect of batter treatments pasting viscosities. Results of this study provide vital information for the potential use of starch types to enhance the rheological properties of coating applications including adhesion and water holding capacity of substituted batter treatment.     

Wet separation of wheat flours into starch and gluten fractions: the combined effects of water to flour ratio–dough maturation time and the effects of flour aging and ascorbic acid addition

The process of making a dough, allowing time for maturation, dispersing the dough in water and wet sieving/washing to obtain a protein fraction and starch milk was studied using response surface methodology by changing the water to flour ratio in dough making (400–710 g kg^?1), maturation time (45–660 s) and the type of flour. Two grades of bread wheat flour and durum clear flour were studied. The effects of aging at ambient temperature for up to 29 days and the addition of ascorbic acid at 100 or 500 mg kg^?1 flour on separation behaviour were also studied for freshly milled high‐grade (65% extraction) bread wheat flours at constant maturation time, 600 s, and at optimum farinograph water absorption value. The quantities and dry matter contents of the protein fraction and starch milk were measured; a sample of starch milk was centrifuged to obtain decantate, tailings and prime starch fractions, and the dry matter contents of each were determined. All the dried samples were also analysed for protein content. The fractional recoveries of dry matter and protein in the protein fraction, prime starch, tailings and decantate were calculated for each experiment. The acid values of flour oils were also determined on some aged flour samples. The results indicated superior separation characteristics in high‐grade wheat flour compared with lower‐grade flours. The water to flour ratio was more influential than maturation time within the range studied. Contrary to the initial expectation, no statistically significant effect of flour aging was observed in the studies with no additive, and ascorbic acid addition was not found to improve the wet separation behaviour, the separation behaviour becoming even worse at the 100 mg kg^?1 level. Acid value showed a slight increase with time. © 2002 Society of Chemical Industry     

Physicochemical characteristics of starches and flours from cassava varieties having different cooked root textures

Starches and flours from 12 cassava varieties having differences in cooked root texture - mealy, firm and mealy & firm - were investigated, with a particular focus on aspects of physicochemical characteristics. It was found that chemical composition (protein, lipid, fiber, ash), pasting properties, firmness of gel, thermal properties, morphology and granular size distribution and crystalline pattern of starches from the 12 varieties were not significantly different. On the contrary, cassava flours which consisted of both starch and non-starch components exhibited wider variations in these properties, especially pasting properties and firmness of gel, than the starches. All flour samples had lower paste viscosities than their corresponding starches. Pasting temperatures of flours were in a range of 70-74 ^°C, which was higher than those of starches (67-70 ^°C). Fluctuation in the values of pasting parameters of flours among the varieties was associated with the variations in the chemical composition and α-amylase activity, i.e. paste viscosity and setback were positively correlated to starch content and negatively correlated to α-amylase activity, while protein, lipid and fiber did not show correlation with pasting parameters. Cassava starches from all varieties, except the F-18 variety, had higher firmness of gels than their corresponding flours. Firmness values (except the F-18 variety) of starches were in a range of 149-207 g, whereas those of flours were 75-163 g. Firmness of flour gels was negatively correlated to lipid and fiber content, while strong positive correlation was found with the amylase activity.     

Biochemical changes in new plantain and cooking banana hybrids at various stages of ripening

BACKGROUND: New varieties of plantain and cooking banana with higher yields and improved pest and disease resistance are continuously being bred. There is therefore the need to study their properties during postharvest ripening. This work investigates the effects of ripening on the dry matter content, pH, titratable acidity, ascorbic acid content, browning potential, starch content and reducing and non‐reducing sugar contents of new FHIA 19 and FHIA 20 plantain and FHIA 03 cooking banana hybrids. RESULTS: The starch and ascorbic acid contents of all hybrids decreased as ripening progressed. The starch and dry matter contents of the FHIA 03 cooking banana were reduced from about 750 to < 100 g kg^?1 and from 260 to 190 g kg^?1 respectively after stage 9 of ripening, when samples had more black than yellow colour. The FHIA 03 cooking banana had the highest content of non‐reducing sugars. The titratable acidity of the FHIA 03 cooking banana was higher than that of the FHIA 19 and FHIA 20 plantains. The browning potential of all hybrids decreased after stage 7 of ripening, when samples were yellow with black spots. The FHIA 19 plantain had the lowest browning potential. CONCLUSION: Significant reductions in the dry matter, ascorbic acid and starch contents of the plantain and cooking banana hybrids were observed during the progress of ripening. The cooking banana variety contained lower levels of dry matter, ascorbic acid and starch than the plantain varieties. Copyright © 2008 Society of Chemical Industry     

Unripe banana flour as an ingredient to increase the undigestible carbohydrates of pasta

Banana is a starchy food that contains a high proportion of undigestible compounds, such as resistant starch and non-starch polysaccharides. There is an excess of production and large quantities of bananas are lost. The objective of this study was to use unripe banana flour as a food ingredient to make pasta (spaghetti) of high quality, on the basis of low-carbohydrate digestibility, and increased resistant starch and antioxidant phenolics contents.