Cold Viscosity Research Articles

KARAKTERISTIK FISIKOKIMIA DAN FUNGSIONAL TEKNIS TEPUNG KORO KRATOK (Phaseolus lunatus L.) TERMODIFIKASI YANG DIPRODUKSI SECARA FERMENTASI SPONTAN

Lima bean (Phaseolus lunatus L.) has a high bioavailability and good of amino acids balanced. Lima bean was pontentially used as a food ingredient on food manufacturing. In order to enhance its properties, the bean flour wasmodified by spontaneous fermentation. The aim of this research was to obtaine the appropriate fermentation pH and time on the production of modified lima bean flour. The fermentation pH were 4.5; 5 and 5.5 in combination with fermentation time of 16, 24 and 32 hour. The Modified lima bean flour was then determined its moisture, ash, fat and soluble protein content. viscosity, bulk density, lightening, oil holding capacity (OHC), water holding capacity (WHC), foaming activity and stability index, emulsifing activity and stability index. The research results showed that the best treatment resulted by fermentation pH of 5.5 for 16 hours. The modified lima bean flour had 8.10 ± 0.68 % water content, 5.52 ± 1.06 % ash content, 0.19 ± 2.18 % fat content, 33.74 ± 1.20 % soluble protein content, 16 ± 0.00 mPas, hot viscosity, 17.33 ± 0.58 mPas cold viscosity, 0.88 ± 0.00 g/ml bulk density, 91.43 ± 0.38 brightness, 250.01 ± 43.76% oil holding capacity (OHC), 189.49 ± 9.17 % water holding capacity (WHC), 28.22 ± 0.40 ml/g foaming activity, 26.52 ± 1.31 % foaming stability, 333.63 ± 6.70 m2/g emulsion activity and 3.66 ± 0.01 hour emulsion stability. Based on those properties, the modified lima bean flour showeh high potency on many food application.

Instant blend from cassava derivatives produced by extrusion

ABSTRACT: The current research aimed to evaluate the effects of extrusion parameters on the physical characteristics of extruded blends of cassava leaf flour and starch. A factorial central composite design with four independent variables and the response surface methodology were used to evaluate the results of color parameters (L*, a*, b*), water absorption index, water solubility index and paste properties, according to the variations in the leaf flour percentage (1.5 to 7.5%), extrusion temperature (60 to 100ºC), screw speed (175 to 231rpm) and moisture (20 to 30%). Extrusion conditions affect color, water absorption and water solubility indexes and paste properties of blends. The intermediate tested conditions of variable parameters lead to obtain extruded products with higher cold viscosity and water absorption index and light color, desirable qualities for rapid preparation products.

Influence of spelt flour addition on properties of extruded products based on corn grits

Production of corn extrudates with addition of various types of flours is widely used in the food process industry, both for final products and for the modification of flours for the bakery industry. Because of its chemical composition spelt is recently used for production of various types of food products. The aim of this study was to determine the effect of spelt flour addition to corn grits (ratios grits: flour=95:5; 90:10 and 80:20) on extrudates properties. Prepared samples with 15% of moisture content were extruded in the laboratory single screw extruder, and then physical and rheological properties were determined.The obtained results showed that addition of spelt flour to corn grits resulted in decrease of expansion ratio (ER) and fracturability, whereas bulk density (BD) and hardness of extrudates increased. After extrusion process water absorption index (WAI), water solubility index (WSI) and damage of starch (DS) significantly increased, while resistant starch (RS) content decreased. Spelt flour addition and extrusion process significantly changed the color, decreased peak, hot and cold viscosities, and the extruded samples were less prone to retrogradation.

Influence of the extrusion process on the technological properties of hydroxypropylated cross-linked cassava starch

Native cassava starch shows limited technological performance, due to considerable cohesiveness and sensitivity to mechanical shear, low pH values and high temperatures. One alternative to overcome these limitations is hydroxypropylation cross-linking, but high temperature/high pressure processes can change the potential applications of these starches. The aim of this study was to analyze the influence of the extrusion process, as a pre-gelatinization method, on the technological properties of hydroxypropilated cross-linked cassava starch. The starch was pre-gelatinized according to a central composite design with two independent variables (x1=die temperature; and x2= moisture content). The dependent variables analyzed by Re- sponse Surface Methodology were swelling power and solubil- ity (at 50, 70 and 90 °C), cold viscosity, peak viscosity, break- down, final viscosity, setback, hardness, fracturability, elastici- ty, cohesiveness, gomositivity, mastigability and resilience, and showed that the independent variables influenced the quality of the pre-gelatinized products with respect to the peak viscosity and cohesiveness (P<0.05). The thermal properties of the hydroxypropilated cross-linked cassava starch and the trials with the extreme levels of the independent variables were also evaluated. Of the independent variables, the moisture content had the greatest effect on the quality of the pre-gelatinized and hydroxypropilated cross-linked cassava starch.

Influence of marine hydrocolloids on extruded and native wheat flour pastes and gels

Extruded and native wheat flours were combined with agars (Gracilaria and Gelidium) and carrageenans (κ-carrageenan and ι-carrageenan) to modify their paste and gel properties. Combinations of extruded flours with hydrocolloids produced an increase in the hydration properties (swelling volume and water holding and water binding capacities). All hydrocolloids (particularly ι-carrageenan) also produced an increase in hydration properties after combination with native flours. With regard to the pasting properties of native flours combinations, all hydrocolloids produced an increase in peak viscosity (particularly Gelidium agar), but only agars decreased the onset temperature of gelatinization and increased breakdown, indicating a different mechanism of action. In the presence of extruded flour, the incorporation of hydrocolloids increased the cold viscosity of flours in very different ways depending on the hydrocolloid. Both native and extruded flours exhibited higher G′ and G″ values and a lower tan δ after the incorporation of carrageenans, which, together with the lower dependence on frequency, would produce stiffer and more stable pastes/gels. Based on gel properties, greatest hardness with native and extruded flours was achieved by the incorporation of carrageenans. In general, carrageenans, besides producing stiffer and more stable pastes, gave rise to harder and clearer gels compared to those made with agar, for both their combination with extruded and native wheat flours. Meanwhile, pastes made with combinations of extruded flours and agar showed higher thixotropy.

Characterization of cassava starch processed in an internal mixer

An internal mixer connected to a torque rheometer was used to investigate the effect of moisture content (13.2 to 46.8 g.100g - 1), rotation speed (13.2 to 46.8 rpm) and processing temperature (53.2 to 86.8 °C), applying a factorial central composite design, on the specific mechanical energy (SME), pasting viscosity and crystallinity of cassava starch. Torque values were highly significant for the three variables, showing decrease with increasing moisture, temperature and rpm. The highest cold viscosity (CV) was obtained at 13.18 g.100g - 1 moisture, 86.87 °C and 30 rpm due to increased rupture of starch granules caused by processing at lower moisture condition. Peak viscosity (PV) values were higher than CV values which indicated that the processing was not able to destroy completely the molecular integrity of the starch granules. Smaller setback (SB) at high temperature and rpm and low moisture showed possible starch depolymerization causing loss of recrystallization capacity. Processing under low moisture content resulted in reduction of crystallinity. The results showed that the effect of moisture was more pronounced than rotation speed and processing temperature of cassava starch.

Extruded corn flour changed the functionality behaviour of blends

Functionalities and relationships between raw and extruded maize flour blends were studied. The extruded flour had higher water absorption and water solubility indices, and had no differential scanning calorimetry endotherm. The parameters of RVA peak, breakdown, setback, and final viscosity were lowered and the parameters of cold viscosity were improved as the fraction of the extruded flour in the mixture increased. In starches from raw flour, a bimodal distribution of the chain length was found by gel permeation chromatography while in the extruded starches only one fraction was observed. The dough quality of 60% raw and 40% extruded flour mixture was found to be better than with other mixture proportions. &amp;nbsp;

Properties of Blends Combined with Corn Flours and Wheat Flours

Rheology of composite flour between corn or extruded flour and wheat flour were studied. Corn flour and extruded flour greatly influenced the water absorption, development time, stability, degree of softening of composite flour. Composite flour (70:30) had better dough quality than other ratios of blends and the cold viscosity was appropriate for preparing dough.

Thermal and pasting properties of cassava starch-dehydrated orange pulp blends

Instant mixtures are easy to prepare and frequently present functional appeals. A quality parameter for instant mixtures is their rheological behavior. This study aimed at evaluating the effects of extrusion parameters on the pasting properties of cassava (Manihot esculenta L.) starch and dehydrated orange (Citrus sinensis (L.) Osbeck) pulp mixtures. The variable parameters were moisture of mixtures (12.5 to 19%), barrel temperature (40 to 90ºC) and screw rotation (170 to 266 rpm). The extruded mixtures did not show gelatinization enthalpy. Moisture had the greatest effect on paste properties. The initial pasting viscosity (before heating) of RVA (Rapid visco analyzer) is the most relevant parameter to instant mixtures. The highest cold viscosity values were obtained when mixtures were extruded under high moisture and high screw speed. High moisture (19.5%), intermediate temperature (65ºC) and screw speed (218 rpm) led to extruded mixtures production with low component degradation.

친환경 무농약 재배와 관행 재배 쌀의 특성비교

The properties of non-waxy rice, Dongjin 1, cultivated with conventional farming (CF) and environmentally-harmonized farming (EHF) using hairy vetch were compared to determine rice water absorption, physicochemical and pasting properties, antioxidant activities of brown and white rice, and a sensory evaluation of cooked white rice was carried out. EHF was treated with green manure crops such as hairy vetch and chitinase, which produce microorganism culture solution. CF was applied with seed disinfection treatments, fertilizer herbicides, and agricultural chemicals for the control of pests and diseases. The absorption level of EHF rice was higher than that of CF rice grain, regardless of the cultivation methods used. The ash and crude lipid contents were higher, but protein and dietary fiber contents were lower in the CF rice than in the EHF rice. The total starch content, water binding capacity, and swelling power of white rice were higher than those of brown rice, regardless of the cultivation methods used. The DPPH`s antioxidant activity was shown as follows: EHF brown rice, EHF white rice and CF rice, in a decreasing order. The initial pasting temperature of EHF rice was lower than that of CF rice, but the peak, cold, and breakdown viscosities exhibited reverse trends. The sensory evaluation showed that the cooked white rice cultivated with EHF was not significantly different from that cultivated with CF (p

Effect of soybean hull, screw speed and temperature on expanded maize extrudates

Summary Brazil is one of the biggest producers and exporters of soybean grains and also produces large amounts of soy for animal feed. However the amount of soy based products for human consumption is surprisingly low in Brazil, due, in part, to the limited preference for soy based products. During the processing of soybeans, a considerable quantity of soybean hull is discarded, but this could be used as an source of insoluble fibre in food products, for example, in extruded expanded products. The objective of this work was to study the effects of soybean hull, moisture content and temperature on the production of expanded maize extrudates. Mixtures of maize grits and soybean hull were extruded in a single screw extruder to produce directly expanded extrudates, and the effects of three independent variables, screw speed (100-200 rpm), temperature (100-200 °C) and soybean hull content (0-40%) were investigated using a central composite rotatable design and response surface methodology. The response variables used in this study were: specific mechanical energy (SME), sectional expansion index (SEI) and the paste viscosity readings (cold viscosity, peak value, breakdown and setback). All the response variables were affected significantly (p < 0.05) by the addition of soybean hull. The interaction between soybean hull and temperature increased breakdown and reduced setback. SME and SEI decreased as the addition of soybean hull and the temperature increased. No significant effect of increasing screw speed on SME and SEI was observed in this study. The sensory evaluation showed that no statistical difference was found between extrudates containing 10, 20 and 30% soybean hull, indicating that maize extrudates containing added soybean hull could be used as a rich source of insoluble fibre.

Characterization of Resistant Starch Samples Prepared from Two High‐Amylose Maize Starches Through Debranching and Heat Treatments

ABSTRACTThe aim of the present study was to investigate effects of debranching, autoclaving‐storing cycles, and drying processes (oven‐drying or freeze‐drying) on RS contents, thermal, pasting, and functional properties of high‐amylose maize starches (Hylon V and Hylon VII). The resistant starch (RS) contents increased (≤57.8%) with increasing autoclaving‐storing cycles. RS contents of oven‐dried samples were higher than those of freeze‐dried samples due to ongoing retrogradation of starch during oven drying at 50°C. Debranching caused a significant decrease in peak transition temperature and enthalpy values as compared with native starches. Solubility and water binding values of RS preparations were higher than those of native starches. Addition of native and autoclaved samples had improving effect on emulsion properties of albumin. Cold viscosity values of oven‐dried samples were lower as compared with freeze‐dried samples; this might be due to higher number of H‐bonds in the oven‐dried samples expected to be formed during drying. Debranching and autoclaving‐storing cycles caused decreases in peak, breakdown, and final viscosity values. The results of present study showed that debranching and heat treatments increased the RS contents and improved the functional properties of high‐amylose maize starches.

Produção de farinha instantânea de mandioca: efeito das condições de extrusão sobre as propriedades térmicas e de pasta

With the advancement of technology, there is the possibility of introduction of differentiated flours, such as cassava instant flour. This alternative has generated great interest from the cassava processing industries. This study aimed to assess the effect of extrusion temperature, moisture content and screw speed on the thermal and viscosity properties of extruded cassava flour. The results showed significant effects of process parameters on the viscosity properties, with effect of screw speed on cold viscosity, viscosity peak and breakdown. The viscosity peak was influenced by the three parameters of extrusion process. No significant effects of operational conditions were observed on the final viscosity and retrogradation. The thermal properties of extruded cassava flours showed no residual enthalpy of gelatinization.

Effect of debranching and heat treatments on formation and functional properties of resistant starch from high-amylose corn starches

High-amylose corn starches [(Hylon V (H5) and Hylon VII (H7)] were debranched with pullulanase, followed by autoclaving–storing cycles and drying in an oven (at 50 °C) or freeze-dryer. The samples were autoclaved at 123 and 133 °C and stored at 4 and 95 °C. Molecular weights of the samples decreased and resistant starch (RS) contents increased with increased debranching time. RS contents of H7 samples were higher than those of H5 samples. RS contents of oven-dried samples were higher than those of freeze-dried samples. Debranching caused decreases in DSC peak temperature (Tp) and increases in enthalpy (ΔH) values of H5 and H7. Autoclaving at 133 °C caused higher ΔH values as compared to autoclaving at 123 °C. The solubility and water-binding values of autoclaved-only (control) and autoclaved–debranched (3–48 h) samples and the samples treated with autoclaving–storing cycles after debranching of both H5 and H7 were higher than those of their respective native starches. Debranching of starch samples affected the emulsion capacity of albumin adversely, but improved the emulsion stability of albumin. Cold viscosity values of freeze-dried samples were higher than those of oven-dried samples. Autoclaving–storing cycles after debranching caused decreases in peak, breakdown and final viscosity values.

Improving effect of lyophilization on functional properties of resistant starch preparations formed by acid hydrolysis and heat treatment

In this study, effects of lyophilization on the functional properties of acid modified and autoclaved corn starch preparations were investigated. RS contents and pasting properties of these starch preparations were also determined. Significant increases in solubility were observed as the hydrolysis level of the lyophilized samples increased. All of the acid-modified gelatinized–autoclaved–lyophilized samples had higher water binding values than those of native starch and heat treated oven-dried native starch. Acid-modified gelatinized–autoclaved–lyophilized samples (with storage at 95°C: GASL or without storage: GAL, before lyophilization) improved emulsion properties of soy protein solution significantly. Acid modification seems to be a prerequisite to achieve improving effect of lyophilization. While native starch did not contain any RS, the level increased to 8.1% due to gelatinization, autoclaving and oven-drying (Control 2). The RS content of Control 2 was higher than that of gelatinized–autoclaved–lyophilized native starch (N-GAL, 2.9%). The samples stored prior to lyophilization had higher RS contents as compared to the corresponding unstored samples. The highest RS content (12.4%) was observed in 2h-GASL sample. Cold viscosity was observed in the RVA curves of N-GASL, 2h-GASL, N-GAL and 2h-GAL samples. A possible mechanism/model is suggested to explain the lack or existence of a cold viscosity.

Preparation of Acetylated Distarch Adipates by Extrusion

Acetylated, cross-linked and pre-gelatinized cassava starches were produced in a single-screw extruder with different moisture contents (180, 220 and 260 g/kg), reagent–adipic acetic mixed anhydride-concentration (4, 11 and 18 g/kg) and screw speeds (100, 130 and 160 rpm). The acetylation, cross-linking and pre-gelatinization steps increased the cold viscosity, water absorption index and gel hardness, and reduced the gel cohesiveness, paste clarity and retrogradation of the starches produced. Products manufactured under less severe operational conditions (260 g/kg moisture and 100 rpm screw speed), and at higher reagent concentration (18 g/kg), had the major group of functional characteristics preferred for puddings, instantaneous desserts and foods subjected to low-temperature storage. Using 260 g/kg moisture, 11 g/kg reagent concentration and a screw speed of 160 rpm, the starch products gave high clarity, no syneresis and could be used in fruit pie fillings, soups and canned foods.

Optimization of the production of acetylated distarch adipates using the novel software ‘MULTIPLEX’

Acetylated, cross‐linked and pregelatinized cassava starches were produced in a single‐screw extruder with different moisture contents (180, 220 and 260 g kg–1), reagent (adipic acetic mixed anhydride) concentrations (4, 11 and 18 g kg–1) and screw speeds (100, 130 and 160 r.p.m.). The acetylation, cross‐linking and pregelatinization increased cold viscosity (CV), water absorption index (WAI) and gel hardness, it also reduced gel cohesiveness, paste clarity and retrogradation of the modified‐starches compared with control samples (CSs). A novel microcomputer program called MULTIPLEX was developed for the optimization of the process. The optimization process maximized CV, WAI, gel hardness and paste clarity, and minimized gel cohesiveness and retrogradation of the modified‐starches. The optimum conditions were moisture of 240 g kg–1, reagent concentration of 4 g kg–1 and screw speed of 100 r.p.m. Experimentally determined values for all responses found in products processed under the optimum conditions were very close to the predicted values and this confirmed the validity of predicted models.

Functional properties of pregelatinized and cross-linked cassava starch obtained by extrusion with sodium trimetaphosphate

Cassava starch was cross-linked with sodium trimetaphosphate (STMP) on a Cerealtec single-screw extruder at different extrusion temperatures and concentrations of STMP and NaOH. The effect of variables on functional properties of the products was analysed by the response–surface methodology. The degree of substitution (DS) was influenced by NaOH and phosphorus level, and increased when their concentration increased. Extrusion temperature affected water absorption, cold viscosity and gel characteristics. The introduction of phosphate groups by cross-linking, with maximum DS of 1.5×10 −4, increased the gel strength, water absorption index, resistance to high temperature and shear, and decreased gel cohesiveness, starch clarity and water solubility index. The products had different DS and degree of gelatinization and thus can be applied in several kinds of foods.

Gelling properties of extruded yam (Dioscorea alata) starch

Yam (Dioscorea alata) starch was pregelatinized in a single screw extruder. Response Surface Methodology was used to study the effect of extrusion variables: feed moisture (18, 21, 24%), extruder temperature (120, 150, 180°C) and die diameter (3, 4, 5 mm) on cold viscosity, gel-forming capacity and retrogradation of extruded starches. Cold viscosity was higher from starch samples processed at higher moisture and die diameter, at lower temperatures. Slurries of the extruded starch (8%, w/v, d.b.) formed opaque and firm gels. Higher values for gel strength were found in samples extruded at highest and lowest moistures at intermediate temperature and increasing die diameter. Gels of extruded starch had lower retrogradation values than non-extruded gelatinized starch after one and two weeks storage at refrigeration temperature. Prediction equations for the studied functional properties can be used in selecting processing conditions for specific food applications.

Effect of Aqueous Ethanol Cationization on Functional Properties of Normal and Waxy Starches

AbstractCationic starch ethers of normal and waxy corn, normal and waxy barley and normal pea starch were prepared by an aqueous alcoholic process for evaluation of their functional properties as compared to the native starch controls. The native starches exhibited a wide range in average granule size (10–21 μm diameter), amylose content (0–34%) and swelling power (13–31). Cationization to degrees of substitution (DS) of 0.030–0.035 with 3‐chloro‐2‐hydroxypropyltrimethylammonium chloride resulted in marked increases in swelling power of all starches, with little corresponding increases in starch solubility. Cationization also decreased the onset of endothermic transitions and pasting temperatures quite substantially, and promoted the development of sharp peak viscosities in the amylographs of all normal and waxy starches, including that of pea starch. Final cold viscosities of the cationic starches exhibited positive setbacks, and the cooked starch gels, after storage for 7 days at 4°C and −15°C, showed no syneresis. All cationic starches except for waxy corn were more susceptible to α‐amylase hydrolysis than native control starches. The general improvement in functional properties, especially in the waxy corn, waxy barley and pea starches, due to the aqueous alcoholic‐alkaline cationization process would greatly enhance their industrial applications.