Storage stability and pasting properties of hydrothermally treated pearl millet flour

Hydrothermal treatment (30 ± 2% moisture and steaming at 1.05 kg m^?2 for 0, 10, 15, 20 and 25 min) was given to whole and pearled pearl millet grains. Flour obtained after each treatment was evaluated for physical, functional and pasting properties. Flour obtained from steamed before pearling (SBP, 20 min) and steamed after pearling (SAP, 15 min) grains exhibited no lipase activity and acceptable physical, functional and pasting properties. Significant (P ≤ 0.05) reduction (28.65%) was observed in total phenol content after pearling. Tannins content of control flour was 120.3 ± 2.15 mg, and a reduction of 25.2% and 16.5% was observed after 20 and 15 min of steaming in SBP and SAP samples, respectively. Significant (P ≤ 0.05) increase in bulk density, functional properties and decrease in pasting properties of treated flour samples was observed with increase in duration of steaming. Selected flour samples (SBP, 20 min and SAP, 15 min) were found acceptable for 50 days when stored in polyethylene pouches (75 μ) at ambient conditions (15–35 °C).     

The effects of acid and oxidative modification on the expansion properties of rice flours with varying levels of amylose

This study evaluates the effects of acid and oxidative modifications on the development of the expansive properties of rice flours with varying levels of amylose. Rice grains of the cultivars Embrapa-7 Taim (high amylose), BRS Firmeza (medium amylose) and Motti (low amylose) were used. The rice flours were modified with lactic acid and oxidised with hydrogen peroxide at concentrations of 4 g H₂O₂/100 g flour and 8 g H₂O₂/100 g flour in 5 h, 21 h and 27 h reactions. The rice flours were evaluated for chemical composition, pasting properties, carbonyl and carboxyl contents and expansion properties. The effects of modification with lactic acid and oxidation with hydrogen peroxide were more intense in the flour with the lowest amylose content. The modification of rice flour with lactic acid promoted a reduction in amylose content and in pasting viscosity; the exception to this finding was the peak viscosity of Motti rice flour. The acid and oxidative modifications not changed the specific volume of biscuits made with Taim (1.33 mL/g) and Firmeza (1.88 mL/g) rice flours, however for the Motti rice flour promoted the development of baking expansion. The specific volume increased of 6.53 mL/g in biscuits with native Motti rice flour to 15.80 mL/g in biscuits made with Motti rice flour oxidised with 8 g/100 g of hydrogen peroxide for 27 h.     

Influence of phosphorylated rice flour on the quality of gluten‐free bread

The chemical modification of rice flour by phosphorylation is an alternative to improve the technological quality of bakery products. The aim of this study was to investigate the effect of phosphorylation process of rice flour on technological properties (specific volume, crumb and crust colour) of gluten‐free breads and the hardening of these breads during two storage temperatures (21 °C and ?24 °C). Breads were made with native rice flour, with phosphorylated rice flour and with wheat flour, used as control. The phosphorylation causes significant reduction in the synaeresis of pastes and in retrogradation tendency of rice flours, varying from 258.7 cP (native rice flour) to 122 cP (phosphorylated rice flour). The breads prepared with phosphorylated rice flour showed reduction in the hardness in both storage temperatures studied and effect on rice bread volume, crumb appearance and colour, demonstrating the possibility of use of the phosphorylated rice flour in gluten‐free breads.     

Iron fortification of finger millet (Eleucine coracana) flour with EDTA and folic acid as co-fortificants

Fortification of staple foods with iron is a feasible strategy to enhance the intake of this mineral. In the present investigation, finger millet flour was explored for its suitability as a vehicle for fortification with iron. Ferrous fumarate and ferric pyrophosphate were added at levels that provided 6 mg of iron per 100 g of the flour, and both were found to be equally effective. Inclusion of EDTA and folic acid, along with the iron salts, significantly increased the bioaccessibility of iron from the fortified flours. The fortified flours were stable up to a period of 60 days. There was a decline in the bioaccessible iron content in the flour fortified with ferric pyrophosphate after 30 days of storage. Heat processing of the flours improved the bioaccessibility of iron from the unfortified and fortified flours. Fortification with iron did not affect the bioaccessibility of the native zinc from the flours.     

Screening of different flours for 3D food printing: Optimization of thermomechanical process of soy and rye flour dough

3D food printing allows the development of personalized food, but it is necessary to diversify the printable recipes to propose a varied food offer. The objective of this project was to explore the printability potential of different flours and to optimize a thermomechanical process (mixing and heating of water and flour) to ensure good print quality. A bibliographic study of 25 flours and an experimental screening of five flours was conducted. Thanks to the previous steps, soy and rye flour were selected because of their interesting nutritional value and their printability potential. An experimental design (10 trials) for each flour showed a significant impact of the process parameters studied (percentage of water content and duration of the thermomechanical treatment) on print quality. The reverse engineering approach demonstrated that the optimal water content is similar for both flour (Soy: 59%, Rye: 60%), but the optimal duration of the thermomechanical treatment is quite different (Soy: 27 min, Rye: 22 min).Industrial relevance textInterest in 3D food printing has continued to grow in recent years. Products with different flavors, shapes and textures have been proposed in many studies. However, print quality is not always easy to predict and to obtain, especially when faced with nutritional or functional constraints. In our study, we developed a 3-steps approach (two screening steps including bibliographic and experimental method and then one optimization step) to propose new edible ink combining interesting nutritional composition and good print quality. To achieve this goal a design of experiments based on two process parameters (water content and duration of thermomechanical treatment) was conducted and a predictive model was established for soy and rye flours. The reverse-engineering method allowed determining the process parameters to use to ensure good print quality and stability of 3D-printed products. This approach could be applied for the development of new edible ink using other flours or integrating different ingredients.     

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     

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.     

FULL-FAT SOY FLOUR EXTRUSION COOKED: PROPERTIES AND FOOD USES

SUMMARY– Full-fat soy flours prepared by the extrusion process were shown to have good nutritive value, flavor, and stability. A flour cooked to a nitrogen solubility index (NSI) of 30 stored well, but the addition of tertiary butyl hydroquinone was necessary to prevent rancidity in flours cooked to 19 and 11 NSI values. The 30 NSI flour was more yellow than a commercial flour cooked to the same degree by a different process. When soy flours were compared in bread to 3 and 6% nonfat dry milk on an equivalent protein, fat, and reducing sugar basis, baking properties were similar. At 15 and 20% levels of soy flour, loaf volume decreased less with the extruded products than with nonextrusion-processed soy flour.     

Effect of the shape of rice starch granules on flour characteristics and gluten‐free bread quality

The effect of three different rice varieties with different starch shapes (Seolgaeng (SG), round starch structure; Samkwang (SK), polygonal starch structure and Boramchan (BRC), polygonal starch structure) on rice flour characteristics and gluten‐free bread baking quality was investigated. Rice flours were produced by dry milling and passed through a 200 mesh sieve. Electron microscopy revealed that the structure of SG grains, with round starch granules, possessed larger void spaces than SK and BRC, composed of polygonal starch granules. For this reason, SG grain had low grain hardness and consequently, it was milled to a fine flour with low damaged starch content. The thermo‐mechanical properties were determined by Mixolab, which revealed that SG was gelatinised rapidly and maintained high viscosity after gelatinisation. These characteristics gave SG flour the ability to build up bread structure without gluten. Specific volume and crumb hardness of gluten‐free rice breads made of SG, SK and BRC flours were 3.37, 3.11 and 2.12 mL g^?1 and 2.61, 2.76 and 6.46 N, respectively. The SG flour with round starch structure is appropriate for making gluten‐free rice breads.     

Rheological and textural properties of lafun,a stiff dough,from improved cassava varieties

We studied the textural and rheological (viscoelastic) properties of fresh lafun dough, a fermented cassava product, and their changes during storage at 45 °C for 5 and 24 h, in order to determine after-cooking storability. Lafun flours were produced from three types of cassava varieties: seven improved white-fleshed varieties, seven improved provitamin A carotenoids (pVAC) varieties and two local white-fleshed varieties; and processed into lafun doughs. Pasting properties of the flours were assessed. Flours from local varieties had pasting profiles with highest viscosities, while pVAC flours had the lowest. The three types of cassava varieties varied significantly in most of their pasting properties. Four promising improved varieties were identified, based on high peak viscosity (55.8–61.5 P) and stiffer texture than local varieties during storage. Undesirable varieties were also found, which softened during storage instead of hardening. Optimum texture of lafun dough was obtained after 5 h of storage.     

Fate of deoxynivalenol and nivalenol during storage of organic whole-grain wheat flour

This study was carried out to determine the level of retention of the mycotoxins deoxynivalenol (DON) and nivalenol (NIV) during 120 days of storage (aging) of flours produced from organic wheat grain naturally infected with Fusarium fungi. Three types of flour (standard white flour prepared by a roller-grinder mill - IRG, whole-grain flour produced by a hammer-crusher mill - IHC and whole-grain flour prepared by a millstone - OMS) were packaged in food-grade paper or polypropylene plastic bags and stored at two different storage temperatures (constant 10 °C or 25 °C). The concentrations of DON and NIV were measured prior to and after storage by means of HPLC-UV detection methods. After 120 days of storage, the concentrations of DON and NIV decreased between 0% and 29% compared to the initial measurements, depending on the combination of experimental factors. The greatest decrease in mycotoxin concentration was observed in the IHC and OMS flours packaged in paper bags and stored at 25 °C. The smallest decrease in mycotoxin concentration was observed in the IRG flours packaged in sealed plastic bags and stored at 10 °C. Statistical analysis showed that the level of retention of DON and NIV depended significantly on the type of packaging material, but did not depend on the type of flour or the storage temperature.     

Utilization of germinated and heat-moisture treated brown rices in sugar-snap cookies

Utilization of germinated brown rice (GBR) in sugar-snap cookies and effect of heat-moisture treatment of the GBR were investigated. Brown rice was germinated at 30 °C for 48 h and then a heat-moisture treatment was conducted for the moistened GBR (17 g/100 g moisture content) at 100 °C for 4 h. Sugar-snap cookies were prepared with white rice, brown rice, GBR and the treated GBR flours, as substitutes for wheat flour (30–100 g/100 g). All cookies containing rice flours, regardless of germination and heat-moisture treatment, required significantly less force to compress than did the wheat flour cookie, and this softening effect was increased as the level of rice flour substitution increased. The cookies made with the GBR flour displayed inferior physical characteristics compared to those with wheat flour, but the cookies containing the treated GBR flour showed improved physical properties with lower moisture content and higher spread factor than those containing untreated GBR flour. The cookies containing the treated GBR flours showed relatively a low degree of firming during the ambient storage. The overall results showed that the cookies with acceptable quality and improved nutrition could be prepared by partial or complete replacement of wheat flour with the heat-moisture treated GBR flour.     

Effect of hydrothermal treatment of runner bean (Phaseolus coccineus) seeds and starch isolation on starch digestibility

The study investigated the effect of traditional soaking and cooking, storage after cooking and freezing (? 18 °C, 21 days) and autoclaving of two varieties of runner bean on starch digestibility. Results achieved were compared with digestibility of isolated starch subjected to similar treatments. The digestibility of native starch from Nata var. seeds was lower after isolation than in raw flour. This starch was characterized by a higher content of fat and lower values of swelling power (SP) and amylose leaching (AML). After the thermal treatment, a significantly higher content of rapidly digestible starch (RDS) was observed both in seeds and starch. It was accompanied by reduced contents of resistant starch (RS) and slowly digestible starch (SDS). In flours from cooked seeds, the content of RDS was observed to be higher than in flours from autoclaved seeds, despite similar changes in contents of other constituents (ash and protein). It was probably due to better starch gelatinization owing to the long-lasting soaking of seeds. This resulted in a greater decrease of amylose content of starch compared to the other flours. Differences in SP, AML and thermal properties between starches isolated from two bean varieties had no influence on their digestibility after cooking. The storage of starch pastes at a temperature of ? 18 °C, unlike that of seeds, resulted in a significant increase in RS content, which shows the importance of other flour components in the process of starch retrogradation.     

Effect of wheat sprout powder incorporation on lipid oxidation and physicochemical properties of beef patties

The aim of this study was to determine the effects of incorporation of wheat sprout flours (WSF) on lipid oxidation and some quality characteristics of beef patties. Two wheat sprout flour samples (WSF1 and WSF2) were obtained by germination, drying and milling of two different wheat varieties. The beef patties were stored at +4 °C for 6 days or at ?18 °C for 180 days and analysed for their proximate composition, pH, sensory properties, colour parameters and lipid oxidation. TBA formation in WSF‐added patties was reduced approximately by as much as 20% when compared to that of the control at the 180th day of the storage, while favourable results were detectable in the storage period at +4 °C. Again, up to 4% WSF1 or WSF2 incorporation gave acceptable sensorial scores to the beef patties. As a conclusion, it was confirmed that WSF could be incorporated into beef patties to improve their quality parameters and retard lipid peroxidation.     

Effect of Soy Flour and Maize Flour Addition on Phase Separation in Moi-Moi from Soaked Cowpea (Vigna unguiculata) and Cowpea Flour from Different Cowpea Varieties

Two improved varieties of cowpea (IT89KO and IT90K-76) and one local variety (lsiocha) were used to investigate the effects of added soyflour and maize flour on the phase separation in moi-moi made from soaked cowpea and cowpea flour. Different levels (5%, 10%, 15%, 20% and 25%) of maize flour, soyflour and a 1:1 blend of soyflour and maize flour (soy/maize flour) were separately added. The moi-moi from the different combinations was evaluated for phase separation and per cent height of the upper layer calculated. Soaking of cowpea reduced the size of the upper layer in moi-moi compared with the use of cowpea flour. The addition of maize flour or the soy/maize flour reduced the upper layer compared with when either flour was added alone. The upper layer of moi-moi made from cowpea flour with added soy flour (21.20%) was significantly higher (p < 0.05) than moi-moi from soaked cowpea with added soy flour (15.2%). Moi-moi with added maize flour made from cowpea flour produced a significantly (p < 0.05) higher mean per cent upper layer (19.72%) compared with that from soaked cowpea (8.95%). Addition of soyflour produced the greatest upper layer for all varieties used. There were no significant (p > 0.05) differences in the per cent upper layers for moi-moi from all cowpea varieties when maize flour was added. Increasing the proportion of added flours increased the size of the upper layer. Complete prevention of the occurrence of phase separation in moi-moi by addition of soy flour and maize flour alone is not feasible.     

Total phenolic and total flavonoid content,antioxidant activity and sensory evaluation of pseudocereal breads

The aim of the study was to investigate the effect of adding (in two different doses 15% and 30%) pseudocereal (buckwheat, amaranth and quinoa) flour on the antioxidant properties and sensory value of breads. Buckwheat flour had the highest phenolic content (7.25 ± 0.23 mg/g dw). The content of total flavonoids in flours was about 2–4 fold higher when compared to breads. The addition of buckwheat flour to wheat bread, particularly in higher dose, was more effective in enhancing antioxidant activity, as evaluated by means of FRAP and DPPH, which increased by 2.36 fold, and 3.64 fold respectively, in comparison with other pseudocereal flours (amaranth, quinoa), which caused, in higher doses, the changes of above parameters within the ranges 1.20–1.79 fold, and 0.60–1.71 fold. Analysis of sensory results of breads showed that addition of buckwheat flour to the dough might improve subjective properties of bread and increase acceptable quality attributes such as taste, colour or odour. All these observations suggest that addition of buckwheat flour into bread can improve antioxidant as well as sensory properties of bread. Bread fortified with pseudocereal flours, and especially with buckwheat flour, may be placed on the market as a functional food.     

In vivo protein quality of new sorghum genotypes for human consumption

The in vivo protein qualities were evaluated in flours from raw sorghum grains (RF) and flours from sorghum grains subjected to heat treatment in an oven (HTF) from the hybrids BRS 305, BRS 309 and BRS 310, developed by the Brazilian Agricultural Research Corporation (Embrapa). There were no differences in feed efficiency ratios among experimental groups. Heat-treated flour from BRS 309 and BRS 310 genotypes had higher protein efficiency ratios and net protein ratio values; however, they did not differ from those of flour from raw grain of BRS 310 genotype. Effects of heat treatment were observed in the BRS 309 genotype. Heat treatment did not affect true digestibility observed for the RF and HTF of the three genotypes. Lysine was the first limiting amino acid of the three sorghum genotypes. The HTF BRS 305 showed the lowest protein digestibility-corrected amino acid score value. Heat treatment improved the protein quality of genotype BRS 309; however, no differences were observed among the other genotypes.     

Effect of lipoxygenase activity in defatted soybean flour on the gelling properties of soybean protein isolate

Soybean lipoxygenase was inactivated to different degrees by dry heating of defatted soybean flour for 0, 5, 10, 15, 20 and 25 min and soy protein isolates were prepared thereof by isoelectric precipitation of the water extract of the defatted soybean flour. The fluorescence emission intensity at 420 nm of the chloroform–methanol extract of soy protein isolates, which was indicator of the existence of peroxidized lipid, varied in parallel with the lipoxygenase residual activity in defatted soybean flours. The dispersion of soy protein isolate showed an increasing turbidity with the increase of lipoxygenase residual activity in the starting defatted soybean flour, suggesting an elevated tendency to form insoluble aggregates during the preparation of soy protein isolate. Small deformation rheological test revealed that the gelling times were shorter for those soy protein isolates derived from low lipoxygenase activity defatted soybean flours than that of high lipoxygenase activity. Frequency sweep showed that G′ of soy protein isolate derived from low lipoxygenase defatted soybean flour was independent of oscillation frequency in contrast to that of derived from non dry-heated defatted soybean flour, the latter showed a marked frequency dependence. Large deformation test revealed that the gel hardness increased about 10 times after dry heating of defatted soybean flour for 20 min. As the increase of the lipoxygenase residual activity, the gel permeability increased markedly, suggesting that soy protein isolate from high lipoxygenase defatted soybean flour produced coarser textured gel, which corresponded well with the results of scanning electron microscopy.     

Encapsulation by spray drying of bioactive components, physicochemical and morphological properties from purple sweet potato

Purple-fleshed sweet potato flour could be used to enhance the colour, flavour and nutrients in food products. Thus, the investigation was to produce encapsulated flours from purple-fleshed sweet potato by spray drying using combinations of various levels of ascorbic acid (5 g kg⁻¹ and 10 g kg⁻¹) and maltodextrin (30 g kg⁻¹ and 100 g kg⁻¹) and to evaluate their effects on bioactive components, physicochemical and morphological properties. Encapsulated flours had higher total phenolic content, antioxidant capacity and water solubility index than non-encapsulated flour. There were no significant differences in anthocyanin content between encapsulated and non-encapsulated flours. However, water absorption index and flavonoids content of encapsulated flours depended on concentrations of ascorbic acid and maltodextrin. In addition, the high concentrations of ascorbic acid and maltodextrin encapsulated flours had higher glass transition temperature as compared to that of lower concentrations. In respect to morphology, the particles of encapsulated flours with high concentration of ascorbic acid and maltodextrin were more aggregated than those encapsulated with lower concentrations. Therefore, flours encapsulated with 10 g kg⁻¹ ascorbic acid and 30 g kg⁻¹ maltodextrin could be used to enhance the antioxidant activities of functional food ingredients.     

Thermo-mechanical rice flour modification by planetary ball milling

Planetary ball milling is presented as an alternative way to improve the native flour properties by physical modification. A grinding protocol was developed by combination of grinding and pause stages. The effect of rotational speed (450–650 rpm) and milling time (10–20 min) on flour properties were determined using RSM method. The effect of milling conditions on flour attributes was significant. With increasing milling speed and time a significant increase in damaged starch, water-absorption and solubility indexes was observed. Changes in functional attributes, intrinsically related to structural and morphological properties of rice flour, were satisfactorily correlated with crystallinity loss, specific surface area and gelatinization degree. Modified rice flours presented pre-gelatinized characteristics which can offer new opportunities for flour applications, for example as ingredient for instant meal product. Flour modification can be controlled by selecting milling conditions. The distinctive characteristic of the planetary ball mill was the fast speed with which the modified flour was obtained which presented intermediate characteristics in relation with native and amorphous state.