Hull Removal Research Articles

Effects of enzyme addition on the nutritive value of broiler diets containing hulled or dehulled Chinese double‐low rapeseed meals

An in vitro and a feeding trial was conducted to investigate the effect of fibre-degrading enzymes A (xylanase + β-glucanase), B (xylanase) and C (xylanase + cellulase) on the nutritive value of broiler diets containing either hulled (22.5% and 23.5% for 4–21 days and 22–42 days of age, respectively) or dehulled (20% and 21.5%) Chinese double-low rapeseed meals (DLRM). Overall, in vitro digestibility of dry matter (DM) or neutral digestibility fibre (NDF) did not differ (p > 0.05) because of meal types; both crude protein (CP) and NDF digestibility was improved (p < 0.05) because of addition of enzymes B or C either to hulled or dehulled DLRM diets. Birds fed dehulled DLRM diets had a higher (p < 0.05) growth rate, feed efficiency and lower (p < 0.05) feed intake than those fed hulled DLRM diets during the overall phase. Enzyme C addition to dehulled DLRM diets resulted in improved (p < 0.05) growth rate and feed efficiency during 4–21 days of age. Enzymes A and B addition elicited a positive response in feed intake and weight gain (p < 0.05), respectively, but did not affect (p > 0.05) feed efficiency. It would appear that the nutritive value of broiler diets containing Chinese DLRM could be improved by appropriate xylanase-based enzymes. Responses of broilers to fibre-degrading enzymes could be highlighted by hull removal of fed DLRM.

Phenolics from walnut ( Juglans regia L.) kernels: Antioxidant activity and interactions with proteins

Walnut ( Juglans regia L.) kernels have important amounts of phenolic compounds. The objectives of the work were twofold: (a) to extract the phenolic fraction from hulls and walnut flour, and to examine its antioxidant capacity and (b) to evaluate the effect of hull removal on solubility of protein fractions from walnut flour. In accordance with their higher total phenolic content, hull extracts had stronger antioxidant activity than had flour extracts. The presence of phenolic compounds decreased protein solubility in walnut flour obtained from whole kernels. Dehulling of kernels significantly improved protein recovery but this result was strongly affected by the solvent system employed. Proteins from whole kernels, especially those extracted with water and NaCl solution, had a reduced solubility, indicating that phenolics bind to proteins when they are dispersed in aqueous media at neutral pH. The results are discussed in the light of the different complex-forming mechanisms that bind phenolics to proteins.

The Effects of Damaged Kernel Caused by Combine Harvester Settings on Milled Rice Free Fatty Acid Levels

ABSTRACTMilled rice surface oil and free fatty acid (FFA) contents determine rice acceptability to the brewing industry. Both could subsequently contribute to beer off‐flavors and thus compromise milled rice brewing quality. Controlling milled rice FFA by harvesting practices could be important in maintaining brewing quality as some rough rice is damaged by hull removal and/or bran disruption during harvesting. To determine the effect of harvester speed on kernel damage, the long‐grain rice variety Cocodrie was harvested at 3 different combine harvester settings and the percent of damaged kernel (w/w) was measured. Combine harvester cylinder speed had a significant effect on rough rice kernel damage. The percentages of damaged kernels for 550, 850, and 1000 rpm cylinder speeds were 1.2%, 4.0%, and 9.0%, respectively. The FFA level of milled rice with varying amount of damaged kernels was investigated over 6 mo of storage. The faster harvester cylinder speeds resulted with time in significantly greater FFA levels in “as‐harvested” rice. The FFA content of 1000 rpm as‐harvested rice almost reached the 0.1% (w/w) level. The greater the amount of damaged kernel, the greater was the milled rice FFA level, and it was significantly greater than milled rice with no damaged kernels during accelerated storage. The as‐harvested rice with 1000 rpm had the highest FFA level, followed by 850 and 500 rpm.

Energy analysis in the screw pressing of whole and dehulled flaxseed

Specific Mechanical Energy (SME) is an important parameter of screw press design and performance. Analysis of SME and its dissipation will improve our understanding of temperature increase during screw pressing, and will in turn lead to better protection of heat sensitive materials, such as alpha-linolenic acid in flaxseed oil. SME, net enthalpy change, and heat loss were estimated from steady state data for screw pressing whole flaxseed and flaxseed with different fraction of hull removal (FHR). The decrease of moisture content and FHR all resulted in significant increases of both oil and meal temperature and net enthalpy change. Conduction dissipated up to half of the mechanical energy input, while convection was low. SME increased significantly from 81.1 to 104.7 kJ/kg when the moisture content of whole flaxseed decreased from 12.6% to 6.3%. SME when pressing whole flaxseed was significantly higher than when pressing dehulled flaxseed.

The effect of hull removal and pearling on Fusarium species and trichothecenes in hulless barley

Fourteen samples consisting of three cultivars of hulless barley (Hordeum vulgare L.), grown commercially in southern Manitoba in 1994, were examined for levels of Fusarium species and seven fusarium trichothecene mycotoxins: deoxynivalenol (DON), diacetoxyscirpenol, 15-acetyldeoxyni-valenol (15ADON), fusarenone-X, HT-2 toxin, neosolaniol and T-2 toxin. Four fractions from each sample were analysed. These consisted of kernels with the hulls still attached, kernels whose hulls had been removed at harvest, kernels that had been dehulled in the laboratory using a deawner, and kernels that had been pearled in the laboratory to 60% of their original weight. A composite sample of the hulls, obtained from the laboratory dehulling, was also tested. Mycotoxins were determined by gas chromatog-raphy-mass spectrometry. DON and 15ADON were the only trichothecenes detected in this study. The greatest numbers of propagules of Fusarium spp. and the highest concentrations of DON and 15ADON were found in the hulls. The average concentrations of F. graminearum Schwabe and DON in barley were reduced: 90 and 49%, respectively, as a consequence of laboratory dehulling; 95 and 59%, respectively, as a result of dehulling during harvest; and 99 and 86%, respectively, as a result of pearling. Results suggest that growing hulless cultivars shows promise for management of mycotoxin problems associated with FHB. Key words: Fusarium graminearum, Fusarium poae, Fusarium avenaceum, deoxynivalenol, 15-acetyldeoxynivalenol, fusarium head blight

Mechanism of seed dormancy in rice

AbstractDormancy in rice (Oryza sativaL.) seed is imposed by certain physical and chemical factors associated with its covering structures, i.e.hull and pericarp. The nature of these germination blocks, their mode ofaction, and processes regulating the release of dormancy are not fully understood. Of nine rice cultivars studied, Ching-shi 15, Stejaree 45, PTB10, and Mahsuri are weakly dormant, and Bansphul, Benaful, Kataktara, Dular, and N22 are dormant. Release of seed dormancy in rice by various treatments, oxidative processes and enzymic changes associated with dormancy, and parallelism between natural and artificially imposed dormancy patterns were examined. The influence of the hull in imposing dormancy was stronger and more prolonged than that of the pericarp. Application of GA3was effective in inducing germination only in weakly dormant cultivars. Dormancy was completely released in all cultivars by subjecting the seeds to moist heat treatment, by removing the hull and pericarp, and by applying GA3after dehulling. Dormant cultivars had higher O2uptake rate and peroxidase activity and lower amylase and dehydrogenase activities than the weakly dormant ones. Hull removal substantially decreased peroxidase activity but enhanced amylase and dehydrogenase activities. Nonanoic acid (C90), a short-chain saturated fatty acid (SCSFA), when exogenously applied to non-dormant seeds imposed dormancy. Dry heat treatment or presoaking in 0.01mKNO3or 0.1mH2O2was very effective in releasing SCSFA-imposed dormancy. Amylase activity was greatly reduced by treatments with nonanoic acid (C90) or ABA. Considering earlier reports and results of the present study, it is proposed that seed dormancy in rice is regulated both by the presence of SCSFAs and ABA in the hull and the pericarp. The relative significance of these substances in cultivars of tropical and temperate origins and its implications in terms of ecogeographic adaptability are discussed.

The Potential for Buffel Grass Renewal from Seed in 16-Year-Old Buffel Grass-Siratro Pastures in South-East Queensland

(1) Seed production by buffet grass (Cenchrus ciliaris) cv. Biloela and soil seed reserves were studied in two 16-year-old buffet grass-siratro (Macroptilium atropurpureum cv. Siratro) pastures in sub-humid south-east Queensland. Ripe fascicles (the dispersal unit) were collected on six occasions from summer to late autumn, placed on the soil surface in nylon mesh envelopes and retrieved at intervals for germination and viability tests. (2) Dormancy of caryopses within fascicles remained high until spring and germination on a per caryopsis basis did not exceed 15% until summer. Hull removal increased germination of younger seeds. There were indications of secondary dormancy during winter. (3) High temperatures break dormancy: treatment for 4-12 weeks at 60 'C of fascicles which had remained dormant on the soil surface for 51 weeks doubled % germination. As soil surface temperatures rarely exceeded 50 0C, this explains the protracted fascicle dormancy in the field. (4) Soil reserves of buffet grass seeds were < 60 m-2 despite 490-2300 fascicles m-2. Large numbers of rotten seeds were found. (5) The poor seedling renewal of buffet grass was associated with low seed production, high dormancy and soil surface temperatures too low to break dormancy rapidly, hence increasing the chance of rotting and predation.

Soaking Studies on Winged Bean (Psophocarpus tefragonolobus L.DC) to Process Full‐Fat Flour and Determine It's Shelf‐Life Stability

Suitable methods to process full‐fat flour from dried winged bean seeds, their effect on trypsin‐inhibitor activity and keeping qualities of the flour were studied. Soaking in 0.5% or 1% sodium bicarbonate solution and boiling for 30 – 45 min was found to be suitable process for hull removal. Dry dehulling methods resulted in only 14 – 22% hull separation, while wet processing treatments were not effective. Soaking the winged bean seeds (12 hr) in 0.5% sodium bicarbonate, sodium carbonate and sodium chloride solutions reduced 30 – 40% of the trypsin inhibitor activity. Winged bean full‐fat flour could be stored for 4 wk under ambient conditions.

Comparison Of Germination Techniques for Wild Helianthus Seeds1

Seed dormancy has hampered previous efforts to study Helianthus sp. and to use them in breeding programs for improving the cultivated sunflower, H. annuus L. Several seed treatments were tested to determine their effectiveness in overcoming the strong seed dormancy found in many wild Helianthus sp. The first treatment (referred to as the complete treatment) involved mechanical scarification of the seed, a 1 h soak in a 100 mg/L solution of gibberellic acid (GA3), plus hull removal. Other treatments were simplifications of this procedure, and three whole seed treatments using GA3 or ethylene. The results indiicate that treatments which removed the hull and seed coat were the most effective, giving germination of over 90% for many species including the hard‐to‐germinate annual desert species. Soaking scarified seeds for 1 h in a 100 mg/L GA9 solution increased germination for some accessions. Soaking whole seeds in 100 mg/L GA3 for 1 h or 50 mg/L 2‐chloroethylphosphonie acid for 16 h did not increase germination. Incubating whole seeds for 10 days in either 100 or 1000 mg/L GA3 increased germination but produced abnormal plants. The complete treatment is recommended despite its complexity because it gives a high germination percentage and varies least from accession to accession.

Oilseed handling and preparation prior to solvent extraction

AbstractThis paper describes cleaning of soybeans, present methods of drying soybeans to facilitate easy hull removal for the production of high protein meal, latest methods of air recirculation for energy efficiency in process drying, latest methods of handling soybeans to facilitate dust control in storage and conveying, conventional methods of dehulling with an emphasis on potential energy savings, cracking of soybeans with high capacity mills with special corrugations to give ideal particle size distribution for efficient dehulling, flaking of soybeans with high capacity mills; and latest innovations in the drying, dehulling, and conditioning of soybeans by use of the fluidbed drier and the microwave vacuum process.

The art of oilseed meal grinding

AbstractMeal grinding must be set up to give a definite and desired product. The original concept of solvent extracted soybean meal grinding was to use the two‐stage grinding system. However, the advent of front end hull removal equipment resulted in the development of the single stage grinding system, utilizing the grinders with just one sifter. This system lends itself well to grinding on stream. Meal grinding installations must be carefully planned to accommodate all parameters, such as desired consistency of finished product, dust control, conveyance systems, placement of all equipment in meal grinding system, and provisions for hot‐meal, or wet‐meal grinding requirements.

Effects of Various Dormancy‐Reducing Treatments on Seed Germination and Establishment of Indiangrass, Sorghastrum nutans (L.) Nash1

Spikelets of indiangrass, Sorghastrum nutans (L.) Nash, from cultivars ‘Cheyenne,’ ‘Holt,’ and ‘Osage’ were subjected to various dormancy‐reducing treatments and subsequently tested for laboratory germination and field establishment. Dormancy‐reducing treatments were: prechilling, hull removal, prechilling followed by hull removal, and hull removal followed by prechilling.A cultivar‐by‐treatment interaction occurred in normal laboratory germination, suggesting cultivar differences in level of seed dormancy, type of seed dormancy, or susceptibility to caryopsis injury resulting from the treatments. Abnormal laboratory germination followed only treatments involving hull removal. Prechilling significantly increased establishment from Holt spikelets and resulted in a nearly significant (.05) establishment increase with those of Osage. Establishment from Cheyenne spikelets was unaffected by prechilling. Establishment from spikelets of all cultivars was significantly reduced following treatments involving hull removal, although in some instances those treatments significantly increased normal laboratory germination.Economic feasibility of prechilling, as a practical means of improving indiangrass establishment, was considered questionable. However, in laboratory tests prechillng did not seem to remove all dormancy, indicating work with other dormancy‐reducing treatments is warranted.Regression analyses indicated that field establishment was affected by seed set and caryopsis weight as well as by spikelet germination. When dormancy was reduced through prechilling, the effect of normal spikelet germination on fieId establishment was largely attributable to variation in seed set.Statistical complications deriving from use of intact spikelets were discussed.