Pearled Grain Research Articles

Improving functional and nutritional profiles of barley flours with diverse starch types through pearling

A comparative analysis of chemical, functional, and digestive parameters was conducted on five new barley genotypes designed for food purposes, differing in starch type, β-glucans, and arabinoxylan content. Both whole and pearled grain flours were examined. Amylose exhibited positive correlations with least gelation capacity (r = 0.60), gelation temperature (r = 0.90), and resistant starch (r = 0.80). Waxy varieties showed greater water-holding capacity, viscosity, and rapid digestibility compared to normal and high-amylose varieties. Pearling (10%) decreased arabinoxylans by 48% and proteins by 7%, while increasing β-glucans by 8% and starch by 13%. Additionally, pearling improved viscosity and hydration parameters across varieties. This allowed normal and high-amylose genotypes to enhance their functional properties and nutritional value through increased β-glucan and resistant starch content. This exploration advances the understanding of barley's functional attributes for food industry and underscores the potential of pearling to augment consumer nutritional value and health-promoting properties.

Effects of pearling on proximate composition, dough rheology, bread-making quality and health-promoting components of elite wheat cultivars

Though the health benefits of whole wheat products have been widely recognized, their less desirable processing qualities limited consumers’ acceptance. Thus, it is imperative to develop processing techniques for balanced nutritional and processing qualities. In this study, we investigated impacts of two grain pearling (debranning) levels on proximate composition, dough rheological properties, food-making quality, arabinoxylans (AXs), alkylresorcinols (ARs) and phenolic acids composition of two elite bread wheat cultivars. Pearled flour (PF) of Zhongmai 175 retained very good dough extensibility (190.7–195.5 mm), while PF of Zhongmai 578 retained medium-to-strong gluten strength and acceptable bread-making quality. Compared to whole wheat flour, PF preserved major portion of the health-promoting components in wheat grains, i.e., 71.4–94.0 % for water-extractable AXs, 68.1–86.3 % for total AXs, 71.4–92.7 % for alkylresorcinols, 85.5–98.9 % for soluble ferulic acid and 67.3–83.3 % for insoluble-bound ferulic acid. Further investigation is needed to understand the effects of different kernel sizes and debranning rates on nutritional profiles of pearled grains. Taken together, our results suggested that grain pearling can be used to produce wheat products with balanced nutritional and processing quality for improved human health.

Impact of milling on the nutrients and anti-nutrients in browntop millet (Urochloa ramosa) and its milled fractions: evaluation of their flour functionality.

Browntop millet has gained popularity in recent years owing to its nutritional superiority and health benefits. However, the usage of browntop millet flours as ingredients in composite flours and functional foods is constrained due to a lack of information regarding the grain composition and its flour functionality. Therefore, the distribution of nutrients, anti-nutrients in browntop millet milled fractions and their flour functionality was evaluated in comparison to whole grain flour. Bran fraction comprised the highest protein (13.7%) and fat contents (27%) among other fractions. Pearling of dehulled grains considerably reduced phytic acid, saponins and flatulence-causing oligosaccharides in pearled grain flours. Besides, this led to the enrichment of soluble fibre, minerals, phenolics and trypsin inhibitors in bran fraction. Milling also impacted flour functionality. Despite its lower water holding ability, dehulled grain flour exhibited significantly higher oil absorption capacity than whole grain flour due to the removal of fibre-rich hull fraction. Although emulsion (45.2%) and foaming capacities (12.5%) were superior in bran flour, foam stability was greater in pearled grain flours. These findings suggest the potential utilisation of browntop millet milled flours as ingredients in the development of distinct food formulations and as partial substitutes to wheat flour in confectionary and bakery products. © 2024 Society of Chemical Industry.

Bioactive Compounds and Antioxidant Capacity in Pearling Fractions of Hulled, Partially Hull-Less and Hull-Less Food Barley Genotypes.

Three food barley genotypes differing in the presence or absence of husks were sequentially pearled and their fractions analyzed for ash, proteins, bioactive compounds and antioxidant capacity in order to identify potential functional food ingredients. Husks were high in ash, arabinoxylans, procyanidin B3, prodelphinidin B4 and p-coumaric, ferulic and diferulic bound acids, resulting in a high antioxidant capacity. The outermost layers provided a similar content of those bioactive compounds and antioxidant capacity that were high in husks, and also an elevated content of tocols, representing the most valuable source of bioactive compounds. Intermediate layers provided high protein content, β-glucans, tocopherols and such phenolic compounds as catechins and bound hydroxybenzoic acid. The endosperm had very high β-glucan content and relative high levels of catechins and hydroxybenzoic acid. Based on the spatial distribution of the bioactive compounds, the outermost 30% pearling fractions seem the best option to exploit the antioxidant capacity of barley to the full, whereas pearled grains supply β-glucans enriched flours. Current regulations require elimination of inedible husks from human foods. However, due to their high content in bioactive compounds and antioxidant capacity, they should be considered as a valuable material, at least for animal feeds.

Bioactive Components and Antioxidant Activity Distribution in Pearling Fractions of Different Greek Barley Cultivars.

In this study, three pearling fractions, namely bran, dehulled grains and pearled grains, derived from fourteen hulled and one hull-less Greek barley cultivars (Hordeum vulgare L.), were analyzed for the protein, ash, β-glucan, phenolic compounds and tocols contents. High variations appeared in the bioactive contents across the barley cultivars and fractions as well. The protein and ash contents decreased from the outer to the inner layers, whereas β-glucans presented an inverse trend. The highest protein and β-glucan contents were in the hull-less cultivar; however, one hulled cultivar (Sirios) exhibited similar β-glucan content, while another (Constantinos) had even higher protein content. The results also revealed that functional compounds were mainly located in bran fraction. Similar trends were also noted for the antioxidant activity. Ferulic acid was the primary phenolic acid in all fractions, followed by sinapic and p-coumaric acids that were dominant in bound form. However, oligomeric flavonoids, such as prodelphinidin B3, catechin, and procyanidin B2, were more abundant in free form. Overall, this study highlights that different barley cultivars can provide pearling flour fractions of varying composition (nutrients and bioactives), which have the potential to serve as nutritionally valuable ingredients in formulations of cereal-based functional food products.

Development of Naked Non-Waxy Black Barley (Hordeum vulgare L.) Cultivar 'Huknuri' with High Anthocyanin Content

Consumer interest in nutrition and health has increased, for other food and industrial applications, including for barley. ‘Huknuri’ is a new naked non-waxy barley cultivar with black lemma. It was developed by the National Institute of Crop Science, RDA, in 2011. The initial cross was carried out in 2002, and an elite line (HB16225-B-B-9) was selected in 2006. Since then, through preliminary yield and advanced yield trials, it was designated as ‘Iksan 100’. It showed good agronomic performance in the regional yield trials from 2009 to 2011 and was released as ‘Huknuri’, possessing high anthocyanin content and black lemma with a non-waxy endosperm. The average heading and maturing dates of ‘Huknuri’ were April 23 and May 29 in paddy fields, which were one day earlier and the same as those of the check cultivar ‘Saessalbori’, respectively. It had a culm and spike length of 87 and 5.0 cm, respectively. It showed 601 spikes per m2, 61 grains per spike, 29.0 g of 1,000-grain weight, and 780 g of test weight. ‘Huknuri’ showed better resistance to Barley yellow mosaic virus and higher water absorption and expansion rates than those of the check cultivar. Its average pearled grain yield in the regional yield trial was 3.44 MT/ha in upland, and 3.56 MT/ha in paddy fields, which were 5% lower and 1% higher than those of the check cultivar, respectively. The anthocyanin content was 180 µg/g, which was higher than that of the check cultivar.

Biochemical Composition of Spring Barley Grain Pearled to Varying Degrees

Abstract Differences in biochemical composition in dehulled and pearled grain samples affected by the various degrees of pearling were studied for spring barley (Hordeum vulgare L.). Twelve covered spring barley and two hulless genotypes were examined. Commercial samples of pearled barley were included for comparison. Covered barley grain samples were pearled using a small-scale barley pearler to obtain dehulled and pearled barley grain products with pearling percentage of 12% and 30%, respectively. Significant differences were observed in the chemical composition between dehulled grain and pearled grain. As the outer layers of the covered grain were removed to a greater degree by pearling, crude protein content, crude ash, total phenolic concentration and radical scavenging activity in the pearled grain significantly decreased (p < 0.001), while starch concentration increased, without changes in the β-glucans concentration. The concentration of phenolic compounds in the dehulled barley grain samples were 1.30 to 1.61 times higher than for pearled grains. There was a significant (p < 0.01) correlation determined among values of dehulled and pearled grain of different barley genotypes in crude protein, starch, and β-glucan content, but no relationship was found in total phenolic content and radical scavenging activity.

Testing and evaluation of CFTRI dal mill for pigeonpea (Cajanus cajan)

This study covers the performance study of CFTRI dal mill using UPAS-120 variety of pigeonpea as untreated and treated grains. The machine performance was carried out in term of maximum grains input and output capacity, dehusking efficiency, milling efficiency, dal recovery, quality index. In dry milling method, it was found that the maximum grains input and output capacity were 83.77 kg/h and 54.86 kg/h, respectively. The machine dehusking efficiency, milling efficiency, dal recovery, quality index, were 98.97%, 89.31%, 75.21%, 89.34%, respectively while the pearled grains, broaken, powder, husk and undehusked grains were 4.35%, 2.90%, 5.68% 16.20, and 0.03%, respectively. The power consumption at no load and load conditions were 0.92 and 1.19 kW/h, respectively. Similarly in wet milling method, the maximum grains input and output capacity were 93.21 kg/h and 63.79 kg/h, respectively. The machine dehusking efficiency, milling efficiency, dal recovery, quality index, were 98.90%, 92.83%, 75.21%, 92.93%, respectively while the pearled grains, broaken, powder, husk and undehusked grains are 2.62%, 2.90%, 4.11% 16.23, and 0.10%, respectively. The power consumption at no load and load conditions are 0.92 and 1.03 kW/h, respectively.

Soluble and bound phenolics of two different millet genera and their milled fractions: Comparative evaluation of antioxidant properties and inhibitory effects on starch hydrolysing enzyme activities

Soluble and bound phenolic extracts of foxtail and little millet whole grains and their milled fractions (dehulled, hull, bran and pearled) were comparatively evaluated for their phenolic contents, antioxidant properties and inhibition of α-amylase and α-glucosidase activities. Although whole grain foxtail millet had higher total phenolic content than little millet, both the millets possess similar total flavonoid contents. Phenolic contents decreased from outer layers to the inner layers in the order hull>bran>pearled grains in millets. Thus, hull and bran fractions possess higher phenolic content compared to other fractions. Hydroxycinnamic acid derivatives accounted for more than 83% to the total phenolic content in soluble and bound extracts of milled fractions. Caffeic, ferulic and sinapic acids were the major phenolic acids in soluble fractions of whole grain millets, while ferulic and p-coumaric acids were present in higher levels in bound fractions. Quercetin was the most abundant flavonoid detected in all the fractions. However, a remarkably high amount of daidzein was found in bran and pearled grain fractions. Milled fractions of millets exhibited various antioxidant activities. Bound extracts of pearled grain fractions with lower phenolic content presented very high metal chelating activity than other fractions. Furthermore, soluble and bound extracts of both the millets inhibited α-amylase and α-glucosidase activities in a dose-dependent manner. These results suggest the potential utility of millets and their milled fractions as ingredients in functional foods for the management of diabetes by controlling oxidative stress and inhibiting α-glucosidase and α-amylase activities.

Variations in Protein Concentration and Nitrogen Sources in Different Positions of Grain in Wheat.

The distribution patterns of total protein and protein components in different layers of wheat grain were investigated using the pearling technique, and the sources of different protein components and pearling fractions were identified using 15N isotope tracing methods. It was found that N absorbed from jointing to anthesis (JA) and remobilized to the grain after anthesis was the principal source of grain N, especially in the outer layer. For albumin and globulin, the amount of N absorbed during different stages all showed a decreasing trend from the surface layer to the center part. Whereas, for globulin and glutenin, the N absorbed after anthesis accounted for the main part indicating that for storage protein, the utilization of N assimilated after anthesis is greater than that of the stored N assimilated before anthesis. It is concluded that manipulation of the N application rate during different growth stages could be an effective approach to modulate the distribution of protein fractions in pearled grains for specific end-uses.

Distribution of Minerals in Wheat Grains (Triticum aestivum L.) and in Roller Milling Fractions Affected by Pearling.

The distribution of minerals in (pearled) wheat grains was measured by synchrotron X-ray fluorescence, and the impact of pearling (0, 3, 6, 9, and 12% by weight) on the mineral composition of flour, shorts, and bran was identified by ICP-MS. The xylem mobile elements (Mn, Si, Ca, and Sr) dominated in the outermost bran layers, while the phloem mobile elements (K, Mg, P, Fe, Zn, and Cu) were more concentrated in the aleurone. Pearling lowered the concentrations of xylem mobile elements and increased the concentrations of most phloem mobile elements in the pearled grains. Molybdenum, Cd, and especially Se were more evenly distributed, and pearling affected their concentrations in milling products less. Pearling (3%) increased the concentration of several nutrients (P, Zn, Cu) in the flour because the bran fractions reaching the flour are enriched in aleurone. The correlations of concentrations of Mg, Fe, Zn, and Cu with that of P suggested their association with phytate.

An on‐site comparative study of yield factors during glume removal, a primary step in the traditional processing of hulled wheats

Glume removal represents the preliminary step of hulled wheat grain processing for human consumption. Einkorn and emmer wheat are two hulled species, cultivated in marginal areas, from the Mediterranean to the Caucasian region, and the subject of investigation in this paper. An experiment has been carried out to compare the yield of the traditional process, used in Turkey and Armenia, and an updated Italian procedure, by means of on-plant samplings. Crushed grains represent a product from all the plants examined. However, the relative amounts of fractions of different size and use, according to each country, varied consistently. The main Italian product is whole pearled grain. The calculated yield factors varied in the following ranges: dehulling: 0.73-0.81 kg kg(-1); food product: 0.82-0.96 kg kg(-1); overall yield: 0.56-0.95 kg kg(-1) excluding unwanted losses, and 0.42-0.74 kg kg(-1) including unwanted losses. This first comparative assay of hulled wheat processing showed that, not considering the kind of product obtained, glume removal can be carried out with good efficiency in continuously operating traditional plants. Modern schemes, however, allow yielding of intact kernels. Some yield factors were highly affected by the available technology, especially when the process was operating discontinuously.

Varietal and Annual Variations of β-Glucan Contents in Korean Barley (Hordeum vulgare L.) and Oat (Avena sativa L.) Cultivars

Varietal and annual variations in the contents of <TEX>${\beta}$</TEX>-glucan fractions per weight grain samples were examined in sixteen covered and eighteen naked barley and five oat cultivars developed in Korea. Also, the effect of pearling on <TEX>${\beta}$</TEX>-glucan content was investigated. Average contents of total, soluble and insoluble <TEX>${\beta}$</TEX>-glucan fractions were 5.25, 3.72, and 1.53%, respectively, in covered barley, and 5.86, 3.51, and 2.35%, respectively, in naked barley. Soluble <TEX>${\beta}$</TEX>-glucan content was higher in covered barley, though total <TEX>${\beta}$</TEX>-glucan content higher in naked barley. The total and insoluble <TEX>${\beta}$</TEX>-glucan contents were higher in pearled grains. Total <TEX>${\beta}$</TEX>-glucan content was higher in waxy barley than in non-waxy barley. Duwonchapssalbori, a two-rowed and waxy naked barley cultivar, was highest in total, soluble and insoluble <TEX>${\beta}$</TEX>-glucan contents. Highly significant positive correlations were observed between total <TEX>${\beta}$</TEX>-glucan and soluble <TEX>${\beta}$</TEX>-glucan contents both in covered and naked barley. There were significant annual variations in total <TEX>${\beta}$</TEX>-glucan content in barley. Average contents of total, soluble and insoluble <TEX>${\beta}$</TEX>-glucans of oat cultivars were 4.33, 3.44, and 0.89%, respectively. Contents of all fractions of <TEX>${\beta}$</TEX>-glucans were higher in barley than in oat. These results would be useful for the breeding of high <TEX>${\beta}$</TEX>-glucan variety and also for the use barley and oat as valueadded food ingredients.

Comparison of Lipid Content and Fatty Acid Composition and Their Distribution within Seeds of 5 Small Grain Species

Barley, oats, rice, sorghum, and wheat, each with two genotypes, were sequentially abraded by an electric seed scarifier. The pearling fines (PF) and pearled kernels (PK) at each cycle were analyzed for lipid (mostly nonpolar) content and fatty acid (FA) composition. The oil content in whole or dehulled grains ranged from 2.18% of a wheat variety to 6.38% of an oat line. Compared with barley and wheat, rice, oat, and sorghum had higher relative % of C18:1 (31.60 to 36.64 compared with 12.15 to 15.61) and lower % of C18:2 (35.69 to 45.44 compared with 50.79 to 61.50). The relationship between oil content in PF and the cumulative level of surface removal essentially describes the distribution pattern of oil content within a seed. Barley, rice, and sorghum had a similar distribution pattern, characterized by a rapid rate of decreasing for the first few outer layers and then by gradual decrease to a flat value toward the inner core. In contrast, distribution within oats was characterized by a gradual reduction in oil content across the seed. The distribution of oil within wheat fell between the former 2 types. For all 10 grains, from seed surface to inner core, C16:0 and C18:0 increased, C18:1 and C18:3 decreased, and C18:2 changed slightly, providing a new reason for improved oxidative stability for pearled kernels. The differences in the changing intensity of FA composition among grain species correspond to those in oil distribution within a seed, while varietal difference in distribution patterns of content and FA composition of lipids within a species was insignificant. This study was the first to document fatty acid distribution across a grain seed. Results provide 2 major reasons for improved oxidative stability of pearled grains: reduced oil content and shift of fatty acids toward more saturated and less unsaturated composition.

Development of Barley Cultivars with Resistance to Scald (Rhynchosporium secalis (Oud.) Davis) in Japan

Hokuriku district in Japan is a major producing area of six-rowed barley, which is mainly consumed as pearled grain. However, the barley cultivated in this region has been damaged by scald, and commercial scald-resistant cultivars need to be developed. The influence of scald on yield reduction (previously addressed in many reports) and on pearled-grain quality was investigated. The whiteness of pearled grain, which is the most important quality in pearled barley, was not affected, but the pearling time tended to increase with the incidence of disease. Appropriate methods to evaluate resistance or susceptibility of cultivars in breeding programs were considered. Artificial inoculation in seedlings is not adequate to determine the resistance of cultivars because an outbreak of the disease has at times occurred after the heading stage. A field test with a source of infection, i.e., scattering leaves that were badly infected by prior inoculation of scald, accelerated the incidence and prevalence of the disease. When the source of infection was applied before the winter snows, it was especially effective in spreading the disease. The field test helped to determine resistant cultivars and breeding lines that inhibited the incidence of scald after the heading stage, although the occurrence of scald fluctuated according to weather conditions. Most Japanese commercial cultivars are highly susceptible in the field, whereas some foreign cultivars exhibit resistance to the dominant race of scald in Hokuriku district. We analyzed the resistance of “Brier” and showed that it was possibly controlled by one dominant gene at the heading stage, an observation that was in agreement with previous reports. On the other hand, three recessive genes are expected to confer resistance at the grain-filling stage. The heritability of resistance at the grainfilling stage was high, which means it is relatively easy to select resistant individuals in a breeding program even if it is controlled by several genes.

Functionality of Barley Proteins Extracted and Fractionated by Alkaline and Alcohol Methods

ABSTRACTThis research optimized the extraction of different protein fractions from barley grains and assessed the physicochemical properties of the fractions obtained. Pearling was first used to remove the grain's outer layers (mainly bran and germ) so that the barley cytoplasmic proteins (albumin and globulin) would be enriched in the pearling flour (PF), while endosperm proteins (hordein and glutelin) would be enriched in the pearled grain flour (PGF). Salt, alcohol, and alkaline solutions were then used to extract different barley protein fractions from PF and PGF. The effects of extraction solvent type, pH, temperature, and extraction time on protein content and extraction efficiency were studied. Aqueous ethanol (55%, v/v) efficiently extracted barley hordein from PGF at 60°C, whereas pH 11.5 alkaline solution was the most efficient for extracting both cytoplasmic and endosperm proteins from barley PF and PGF at 23°C. Subunit molecular weight, amino acid composition, and the functional properties of each isolated barley protein fraction were investigated. Barley glutelin demonstrated superior oil‐binding property and emulsifying stability, whereas barley hordein exhibited good foaming capacity.

Effect of Outer Bran Layers from Germinated Wheat Grains on Breadmaking Properties

ABSTRACTWheat grains were germinated in the dark at room temperature (24°C) for 1, 2, 3, 5, and 8 days. Germinated wheat grains were pearled in a Waring blender, and the outer bran layers were separated from the pearled grains. Breadmaking was performed with wheat flour and 10% of the outer bran layer. Breadmaking properties (bread height [mm] and specific volume [cm3/g]) were gradually enhanced by blending the germinated outer bran layers, and maximum specific volume was obtained after 5 days of germination. However, the improvement was lost after 8 days of germination. Rapid ViscoAnalyser (RVA) and Brabender Farinograph profiles of wheat flour and outer bran layers (10%) indicated that the maximum decrease of peak viscosity and increase of angle of tail were obtained after 3 and 5 days of germination, respectively. Those changes are presumed to be due to the action of enzymes found in the outer bran layers. Activities of α‐ and β‐amylase, lipase, protease, and xylanase in the outer bran layers were measured, and correlation coefficients (r) between breadmaking properties and peak viscosity (RVA), angle of tail (farinograph), and enzyme activities were calculated. These data suggest that xylanase and α‐amylase activities in the outer bran layers were highly related to the enhancement of the breadmaking properties.

Breeding of a new food barley cultivar "Shiratae Nijo" exhibiting no after-cooking discoloration

Shiratae Nijo is a new two-rowed food barley cultivar bred at the National Agricultural Research Center for Kyushu Okinawa Region (KONARC) in collaboration with the National Institute of Crop Science (NICS) and released in 2009. Shiratae Nijo is a proanthocyanidin-free cultivar bred by backcross breeding using a leading cultivar Nishinohoshi as a recurrent parent and a foreign proanthocyanidin-free mutant ant28-494 as a non-recurrent parent. The agronomic characteristics of Shiratae Nijo are almost the same as those of Nishinohoshi which has high yield performance and high resistance to barley yellow mosaic virus (BaYMV) type I and powdery mildew. Like Nishinohoshi, Shiratae Nijo shows high resistance to Fusarium head blight (FHB) at the anthesis stage but is susceptible 10 days after anthesis. Shiratae Nijo exhibits significantly weaker seed dormancy than Nishinohoshi. Shiratae Nijo has excellent pearling quality, and the pearled grains show no discoloration and high whiteness after cooking because of the lack of catechin and proanthocyanidin in the grains.

In Vitro Bile‐Acid‐Binding of Whole vs. Pearled Wheat Grain

ABSTRACTHealth benefits of consuming whole grains are reduced risk of heart disease, stroke, and cancer. The U.S. Health and Human Services and USDA dietary guidelines recommend consumption of 6–10 oz of grain products daily and one‐half of that amount should contain whole grains. Whole grains contain vitamins, minerals, fiber, and phytonutrients. Bile‐acid‐binding capacity has been related to cholesterol lowering potential of food fractions. Lowered recirculating bile acids results in utilization of cholesterol to synthesize bile acid and reduced fat absorption. Secondary bile acids have been associated with increased risk of cancer. Bile‐acid‐binding potential has been related to lowering the risk of heart disease and that of cancer. It has been reported that bile‐acid‐binding of wheat bran is not related to its total dietary fiber (TDF) content. Whole (W) grain as well as pearled (P) hard red winter wheat (Hrw), hard white winter wheat (Hww), and durum wheat (DU) cooked grains were evaluated for in vitro, bile‐acid‐binding relative to cholestryramine (a cholesterol lowering bile‐acid‐binding drug). On dry matter basis (db) relative bile‐acid‐binding values were 7.7% WHrw; 7.5% WHww; 6.3% PHww; 6.0% PHrw; 5.5% WDU; and 5.4% PDU. On a TDF basis, binding values were 42–57% of that for cholestyramine for the whole and pearled wheat grains tested. Bile‐acid‐binding values (db) for WHrw and WHww were similar and significantly higher than those of PHww, PHrw, WDU and PDU. Similar bile‐acid‐binding of WHww to that of WHrw suggest that the red color commonly associated with whole grain may not necessarily indicate more healthful potential. Data suggest that cooked WHrw and WHww wheat have significantly higher health‐promoting potential than pearled grains. WDU or PDU wheat health‐promoting potential was similar to that of PHww or PHrw. Consumption of products containing WHrw and WHww are recommended.

Effect of wheat pearling on flour phytase activity, phytic acid, iron, and zinc content

This study examined the effect of wheat pearling on distribution of phytase, phytic acid, iron, and zinc in wheat fractions derived from pearling and roller milling. Grains of four wheat varieties were first pearled by a rice polisher at four levels, i.e. non-pearling (unpearled), 5% pearling (∼5% of the original sample weight was pearled), 10% pearling, and 15% pearling, to produce pearling fines (PF) and pearled grains. The unpearled and pearled grains were then milled through a Bühler MLU-202 laboratory mill, producing eight milling fractions. Results showed that pearling had a positive effect on flour yield, which may be attributed to the reduced yield of coarse bran and the improved yield of first and second reduction fractions. PF had high levels of all the four components, indicating that they could be a valuable source of iron and zinc. In addition, the differences between flours from the pearled and unpearled wheat were slight in terms of these four components.