Mohammed Saleh

Effect of Moisture Content at Harvest and Degree of Milling (Based on Surface Lipid Content) on the Texture Properties of Cooked Long-Grain Rice

ABSTRACT The effects of the degree of milling (based on surface lipids content [SLC]) on cooked rice physicochemical properties were investigated. Head rice yield (HRY), protein, and SLC decreased with increasing milling, while the percent of bran removed and whiteness increased. Results showed that SLC significantly (P < 0.05) affected milled as well as cooked rice properties across cultivar, moisture content (MC) at harvest, and location (Stuttgart, AR, and Essex, MO). Cooked rice firmness ranged from 90.12 to 111.26 N after milling to various degrees (SLC). The decrease in cooked rice firmness with increasing milling was attributed to the lowering of total proteins and SLC. Cooked rice water uptake increased with increasing degree of milling. Water uptake by the kernel during cooking dictated the cooked rice firmness. The increase in cooked rice stickiness with increasing degree of milling was attributed to an increase in starch leaching during cooking because of the greater starch granule swelling ass...

Measurement of Conjugated Linoleic Acid (CLA) in CLA-Rich Soy Oil by Attenuated Total Reflectance−Fourier Transform Infrared Spectroscopy (ATR−FTIR)

Conjugated linoleic acid (CLA) isomers in oils are currently measured as fatty acid methyl esters by a gas chromatography-flame ionization detector (GC-FID) technique, which requires approximately 2 h to complete the analysis. Hence, we aim to develop a method to rapidly determine CLA isomers in CLA-rich soy oil. Soy oil with 0.38-25.11% total CLA was obtained by photo-isomerization of 96 soy oil samples for 24 h. A sample was withdrawn at 30 min intervals with repeated processing using a second batch of oil. Six replicates of GC-FID fatty acid analysis were conducted for each oil sample. The oil samples were scanned using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and the spectrum was collected. Calibration models were developed using partial least-squares (PLS-1) regression using Unscrambler software. Models were validated using a full cross-validation technique and tested using samples that were not included in the calibration sample set. Measured and predicted total CLA, trans,trans CLA isomers, total mono trans CLA isomers, trans-10,cis-12 CLA, trans-9,cis-11 CLA and cis-10,trans-12 CLA, and cis-9,trans-11 CLA had cross-validated coefficients of determinations (R2v) of 0.97, 0.98, 0.97, 0.98, 0.97, and 0.99 and corresponding root-mean-square error of validation (RMSEV) of 1.14, 0.69, 0.27, 0.07, 0.14, and 0.07% CLA, respectively. The ATR-FTIR technique is a rapid and less expensive method for determining CLA isomers in linoleic acid photo-isomerized soy oil than GC-FID.

Development and Validation of Prediction Models for Rice Surface Lipid Content and Color Parameters Using Near-Infrared Spectroscopy: A Basis for Predicting Rice Degree of Milling

ABSTRACT Degree of milling (DOM) of rice plays a key role in determining rice quality and value. Therefore, accurate, nondestructive, quick, and automated surface lipid content (SLC) measurement would be useful in a commercial milling environment. This study was undertaken to provide calibration models for commercial use to provide quick and accurate evaluation of milled rice SLC and Hunterlab color parameters (L,a,b) as indications of rice DOM. In all, 960 samples, including seven cultivars from seven southern United States locations, stored for 0, 1, 2, 3, and 6 months, were milled for four durations to obtain samples of varying DOM. The samples were used to develop calibration models of milled rice SLC and L,a,b values. Another sample set (n = 58) was commercially milled and used to validate the developed models. A DA 7200 diode array analyzer was used to scan milled rice samples in wavelength spectra of 950–1,650 nm. SLC and color parameters were measured using a Soxtec system and a HunterLab colorime...

Broken rice kernels and the kinetics of rice hydration and texture during cooking

BACKGROUND During rice milling and processing, broken kernels are inevitably present, although to date it has been unclear as to how the presence of broken kernels affects rice hydration and cooked rice texture. Therefore, this work intended to study the effect of broken kernels in a rice sample on rice hydration and texture during cooking. Two medium-grain and two long-grain rice cultivars were harvested, dried and milled, and the broken kernels were separated from unbroken kernels. Broken rice kernels were subsequently combined with unbroken rice kernels forming treatments of 0, 40, 150, 350 or 1000 g kg(-1) broken kernels ratio. Rice samples were then cooked and the moisture content of the cooked rice, the moisture uptake rate, and rice hardness and stickiness were measured. RESULTS As the amount of broken rice kernels increased, rice sample texture became increasingly softer (P < 0.05) but the unbroken kernels became significantly harder. Moisture content and moisture uptake rate were positively correlated, and cooked rice hardness was negatively correlated to the percentage of broken kernels in rice samples. CONCLUSION Differences in the proportions of broken rice in a milled rice sample play a major role in determining the texture properties of cooked rice. Variations in the moisture migration kinetics between broken and unbroken kernels caused faster hydration of the cores of broken rice kernels, with greater starch leach-out during cooking affecting the texture of the cooked rice. The texture of cooked rice can be controlled, to some extent, by varying the proportion of broken kernels in milled rice.

Milled Rice Fissure Formation Kinetics

Milled rice samples at various moisture contents (MCs) were exposed to air inside a chamber that was equipped with a video camera and monitoring system that enabled observation of fissure formation over 24-h exposure durations. The effects of milled rice kernel MC (11%, 12%, 13%, or 14%), cultivar (Bengal, Wells, and CL161), air relative humidity (RH; 10%, 20%, 30%, 45%, 60%, 75%, or 90%), and air temperature (5°C, 10°C, 15°C, 20°C, or 30°C) on the rate and amount of kernel fissuring were quantified. Rice cultivar and MC played minor roles in determining the rate and amount of fissuring relative to air temperature and RH. Fissuring rates were greatest at low (10%) and high (90%) RH levels; fissuring occurred almost immediately after kernels were exposed to these RH levels. Greater air temperatures considerably increased the rate and total amount of fissured kernels. Little fissuring was observed in an RH range of 30% to 75%, at any air temperature tested, providing a safe window for milled rice exposure to environmental conditions.

Effect of Stabilized Rice Bran Fractions on the Formation of Rice Flour Pasting Properties

ABSTRACT Rice flour composition played a key role in determining the changes in pasting properties of rice flour. The influence of incorporating defatted rice bran (DFRB), rice bran fiber (RBF), rice bran protein (RBP), and stabilized rice bran (SRB) fractions on the mechanism of rice flour pasting viscosities was investigated. Pasting properties of long- and medium-grain rice flour substituted with 5, 10, 15, 20, and 100% bran fractions resulted in a significant decrease (P < 0.05) in rice flour pasting property values. Flour substituted with RBP had the lowest pasting property measurements compared with other fractions, and the greater the percentage substituted, the lower the pasting property values. DFRB and RBF were least affected properties when used as a replacement. Results were attributed to the contribution of rice starch in the mechanism of rice paste formation, in which decreasing starch in a rice flour sample, as a result of substituting with fractions of SRB, may have resulted in faster swel...

Pasta quality as impacted by the type of flour and starch and the level of egg addition

This study investigated the effects of substituting wheat flour with fractions of different starch types and egg levels on pasta quality. First order mixture response surface model was used where the effects of various starch types and egg levels on pasta quality were evaluated. Coefficients of estimation were determined and fractional contribution of wheat, starch type and egg levels were evaluated. Egg levels negatively (p < .05) impacted treatments pasting viscosities, except in potato starch and rice flour. Stabilized rice bran peak viscosity increased from 215.0 to 3420.0 cP with decrease in egg level from 33 to 0%. Flow behavior index of treatments solution with various fractions of starch types and egg level ranged from 0.34 to 1.42 and was significantly (p < .05) lower than control (i.e., 2.15) indicating a better fit as a shear thinning model. Water holding capacity values of acorn starch and lupine flour were the greatest among treatment ranging from 86.8% to 176.0% and from 83.3% to 152.0%, respectively. Results also showed a possible modification of cooked pasta quality including firmness, stickiness, cooking loss, and water uptake, keeping with consumer acceptability through varying starch type and egg level. PRACTICAL APPLICATIONS Results show that flour and starch type and egg level interaction play significant role in pasta blends formulation. Moreover, substitution of wheat flour with acorn, native or modified corn and potato starches fractions, as well as with lupine, rice, tapioca, and stabilized rice bran flours would have significant effects on the physical properties and acceptability of various cereal products. For instance, the use of rice bran in potentially developed products would enhance the consumption of whole grain foods, resulting in improved intake of fiber and other healthy components.

Predicting farinograph parameters by rapid visco analyser pasting profile using partial least square regression

Farinograph parameters are widely used to predict flour and dough functionality. Accurate prediction of farinograph parameters using other instruments would provide key information in determining cereal products quality and functional properties. This study was undertaken to provide calibration models using rapid visco analyser (RVA) to predict farinograph flour parameters and dough end-use functionality. A total of 267 samples consisted of wheat flour substituted with various ratios of disrupted chickpea (Cicer arietinum) and lentil (Lens culinaris) flours were used in this study. Samples (n=237) were randomly selected and used to develop calibration models of farinograph parameters using RVA profile. Another sample set consisting of 30 flour samples were used to validate the developed models. The partial least squares regression method using the RVA profile was used to develop prediction models for farinograph parameters treatments. Farinograph parameters (water absorption, peak time, mixing tolerance i...

Effects of Hydocolloids as Fat Replacers on the Physicochemical Properties of Produced Labneh

This study was undertaken to investigate the effects of hydrocolloids when used as fat replacers on the physicochemical properties of Labneh. Four combination sets of carboxymethylcellulose, Arabic gum, carrageenan, and xanthan were used in a three factor mixture response surface methodology. Labneh water holding capacity (WHC), viscosity parameters, texture and sensory attributes were assessed. WHC played the critical role in affecting produced Labneh physical properties. Hydrocolloids influenced Labneh WHC in the following order; xanthan > Arabic gum > carrageenan > carboxymethylcellulose. Furthermore, xanthan showed an antagonistic effect with carboxymethylcellulose that lead to the decrease in WHC. Usage of 17% xanthan and 66% Arabic gum resulted in an increase in WHC to 98.6% which indicates a mixture response effect of hydrocolloids in affecting WHC of produced Labneh. The increase in carrageenan from 17% to 66% resulted in an increase in WHC from 62.7 to 70.7%. Consumer testing showed a superior Labneh sensory attributed using various hydrocolloids combinations compared to a control. Hydrocolloids were successfully used in Labneh as fat replacers. The developed reduced fat Labneh with its texture and sensory attributed that exceeded the full fat Labneh attributed can provide a solution to consumers with restricting fat diets. PRACTICAL APPLICATIONS Carbohydrate-based fat replacers are of growing interest because of their physicochemical, sensorial properties, and health characteristics. The used hydrocolloids suggest plausible texture and sensory attributes solution in low or reduced fat content products including dairy products.

Effects of incorporating nonmodified sweet potato (Ipomoea batatas) flour on wheat pasta functional characteristics

The effects of substituting wheat flour using fractions of blanched or nonblanched sweet potato flour on produced pasta functional characteristics were investigated. The use of sweet potato flour to replace fractions of wheat flour, regardless of blanching treatment, resulted in significant (p < .05) increase in water holding capacity (WHC), cooked pasta water uptake and solid leaching out and freeze-thaw stability of produced pasta. For instance, treatment containing 40% of nonblanched sweet potato flour and held at 55C resulted in 27% point increase in WHC compared to the control. Sweet potato flour was also contributed to the decrease in treatments pasting viscosities and in cooked pasta hardness. Cooked pasta hardness was significantly (p < .05) decreased from 255.6 N to 187.5, and 152.6 N when using 15% blanched and 40% nonblanched sweet potato flour replacements, respectively. Flow behavior index of wheat flour treatments containing fractions of sweet potato flour were fitted in a shear thinning model. Quality indices of pasta made using fractions of sweet potato were equivalent to or sometimes superior to that of the control sample. Results indicated the possible enhancement of pasta nutritional quality including firmness, cooking loss, and water uptake without impairing consumer acceptability. PRACTICAL APPLICATIONS The use of sweet potato flour in pasta would enhance the nutritional and physicochemical properties of developed pasta and pasta products. Furthermore, since sweet potato is not cultivated most of the year; sweet potato flour pasta would be better utilized in food processing and is expected to enhance sweet potato consumption year around.