• Journal of Practical Agriculture & Fisheries Research
• /
• v.3 no.1
• /
• pp.102-115
• /
• 2001

Through out the last few decades, processing methods for ingredients of feed grains, such as grinding, flaking, extrusion, soaking, cracking etc., have been adopted in order to improve the nutrient digestibility in ruminants. Among feed grains, processing methods for whole corns have been the most frequently studied since corns are utilized as the thumb ingredients in formulating feeds. In these days, flaking of whole corns is the most incessantly used in formulation feeds, resulting in enhancing the performance of ruminants. Recently formulating non-forage feed for beef cattle, especially Holsteins, without processing whole corns is carrying out through various feed companies with expectations of whole corns acting like forages. However, it can not be ruled out that whole corns might possibly result in decreasing the productivity due to the depression of nutrient utilizations. Therefore, one must reevaluate the non-forage feeds as well as makes an effort to develop the rational and effective methodology in processing whole corns with the consideration of rumen eco-system.

• Asian-Australasian Journal of Animal Sciences
• /
• v.15 no.6
• /
• pp.851-858
• /
• 2002

This study was conducted to determine effects of whole (intact), coarsely-ground (4 mm), finely-ground (1 mm), steam-flaked and steam-flaked-ground (1 mm) corns on in vitro and in situ DM digestibilities and also in vitro fermentation characteristics. After 48 h incubation, in vitro dry matter digestibilities of whole, steam-flaked, coarsely-ground, steam-flaked-ground, and finely-ground corns were 6.79, 61.68, 76.48, 85.72 and 90.31%, respectively. Steam-flaked-ground corn showed the highest digestibility until 24 h incubation (p<0.01). After 48 h incubation, pH of whole corn decreased with a small range. However the values of pH of other media significantly decreased (p<0.01). The gas productions of finely-ground and steam-flaked-ground corns were higher than those of the other corns (p<0.01). After 24 h incubation, $NH_3$-N concentration of finely-ground and steam-flaked-ground corns increased rapidly. Total VFA was the highest in finely-ground corn, followed by steam-flaked-ground, steam-flaked, coarsely-ground and whole corns. Incorporating steam-flaked corn resulted in the highest propionate concentration (p<0.01) and the lowest acetate : propionate value (p<0.05). Finely-ground corn showed the highest in situ DM digestibility throughout the incubation period (p<0.01), followed by coarsely-ground, steam-flaked and whole corns, respectively. Overall, DM of whole corn was merely digested in vitro as well as in situ.

• Journal of Life Science
• /
• v.19 no.1
• /
• pp.65-74
• /
• 2009

The objective of this study was to examine the effects of steam flaking treatment of corn grains imported from USA and India on in vitro gas production, microbial growth and contents of aflatoxin $B_1$ and ochratoxin A. Each treatment was composed of total 4 treatments including (1) USCW (US com-whole type), (2) USCF (US corn-flaked type), (3) IDCW (India corn-whole type) and (4) IDCF (India orn-flaked type) with 4 replications $\times$ 6 incubation times (3, 6, 9, 12, 18 and 24 hr). Mycotoxin (aflatoxin $B_1$ & ochratoxin A) contents in test corns tended to increase gradually with increasing logistics periods from the harbor, hopper, silo to processing line. The contents of aflatoxin $B_1$ in India corn (IDCW) and US corn (USCW) were 11.71 and 1.78 ppb, respectively when measured at the hopper. After steam flaking, both contents of aflatoxin $B_1$ in USCW and IDCW were 0.00 ppb. It means that Aspergillus flavus could be decreased by steam flaking. However, this trend was not observed in ochratoxin content. The gas production rate of USA corns (USCW & USCF) was significantly (p<0.05) higher than India corns (IDCW & IDCF), and that of steam flaked corns (USCF & IDCF) was higher $1.5{\sim}2%$ than whole corns (USCW & IDCW) after 3 hr incubation in in vitro experiment. pH value was optimally maintained for microbial growth during whole incubation times with the value of 6.05 to 6.54, and was not significantly different between treatments, but USCF was somewhat lower than other treatments. pH value decreased following 12 hr of incubation but gas production increased rapidly during the same period. In addition, in vitro microbial growth rates also increased with up to 18 hr of incubation period, thereafter experienced a decrease with extended incubation time. In conclusion, US corn was superior to India corn by origin based on the results of in vitro and mycotoxin contents. And steam flaking process of imported corns tended to decrease mycotoxin contents such as aflatoxin $B_1$ and ochratoxin A as well as improve in vitro gas production and microbial growth rates.

• Journal of Animal Science and Technology
• /
• v.45 no.3
• /
• pp.421-432
• /
• 2003

The objective of this study was to examine the effects of processing methods of corn grains on protein and starch degradability in the rumen by three ruminally cannulated dry Holstein cows. The corns for these experiments were untreated; whole corn L(density; 660 g/$\ell$), whole corn H(density; 740 g/$\ell$), and treated by four different types: Ground corn, 3.8 mm, 2.8 mm, and 1.5 mm flaked corn. The results obtained were summarized as follows: For 48 hrs, the protein degradabilities were high in order, ground corn, 1.5 mm, 2.8 mm, and 3.8 mm flaked corn(82.6, 76.5, 64.5, and 33.9%, respectively). Flaked corn grains were degraded lower than ground corn. However, as increasing the processing degree of flaking, the protein degradabilities, from 4 hrs to 48 hrs, were increased. The starch degradabilities on 48 hrs were higher in 1.5 and 2.8 mm flaked corns, ground corn, 3.8 mm flaked corn(99.1, 91.5, 89.5, and 68.9%, respectively) than whole corn L(32.0%) and whole corn H(20.5%)(P<0.05). By increasing the processing degree of flaking, the protein degradabilty between 2.8 mm and 3.8 mm was increased significantly from 68.9% to 91.5%, however, that of 1.5 mm flaked corn, processed thinner, tended to be increased slightly, but was not significantly different. From 12 hrs to 24 hrs, whole corn L was degraded little more than whole corn H in starch, was not significantly different. However, after 48 hr incubation in the rumen, whole corn L was degraded more 50% than whole corn H(P<0.05). The value of degradation parameter “a” of protein was lower in all flaked corns than in ground corn. In contrast, the value of degradation parameter “a” of starch was significantly higher in all flaked corns than in ground corn(P<0.05). It seemed that by flaking the corn grains, starch particles were gelatinized, and then, starch was degraded more rapidly, while protein was degraded more slowly. Referring to these kinds of physical characteristics of grain sources in ruminal degradabilities, it is possible to synchronize the fermentation of nitrogen and carbohydrate sources, in formulating the cattle diets.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.37 no.4
• /
• pp.308-314
• /
• 2017

This study was conducted with two ruminally cannulated Holstein steers to examine the effect of micronized and steam flaked corn on ruminal fermentation characteristics. The in situ dry matter degradability after 48 h incubation was the highest (P<0.05) at micronized corn (2.5 mm thickness) compared with steam flaked corn treatments. The steam flacked corn (3.3 mm thickness) was degraded lower (P<0.05) than the 2.9 and 3.1 mm thickness of steam flacked corn. Effective dry matter degradability and the rate of constant were the highest (P<0.05) at micronized corn (2.5 mm thickness) compared with steam flaked corns as well. The in vitro dry matter degradability after 48 h incubation was tended to higher (P=0.088) at micronized corn (2.5 mm thickness) than steam flaked corns, whereas there is no significantly difference between steam flaked corn treatments. Total volatile fatty acid concentration was higher at steam flaked corn (2.9 mm thickness) than micronized corn (2.5 mm thickness) and steam flaked corn (3.1 and 3.3 mm thickness). The acetate : propionate ratio was the highest (P=0.008) at steam flaked corn (2.9 mm thickness) and the lowest (P=0.008) at micronized corn (2.5 mm thickness). Total gas and methane production after 48h ruminal incubation was the highest (P=0.001) at micronized corn (2.5 mm thickness) compared with steam flaked corns. According to these results, the thickness of steam flaked corn as resulted corn processing is believed to do not affect methane production. However, further study is needed to better understand the present results to verify the correlation between corn processing method and their thickness on methane production using the same thickness corns by difference processing methods.

• Journal of Biosystems Engineering
• /
• v.35 no.3
• /
• pp.163-168
• /
• 2010

With income growth and "well-being" trends, sales of corn has been increased recently. Corns are processed at processing facilities on the main production site. Corn processing steps include removing bract, steaming, vacuum packing, and storing. To replace manual corn bract removing, some bract removing machines were imported and used. However, the machines were abandoned shortly, because of high damaging ratio of corns. In this research, factors of successful bract removing was studied with rotating rollers and air-injection nozzles to develop corn bract removing system. The test device was composed of a cylindrical roller, an air spray nozzle, a regulator, and a motor. Designing factors were roller type, diameter of air spraying nozzle, spraying angle, and spraying pressure. The measured factors were bract removing rate and damaging rate. It was found that optimum cylindrical roller surface shape was cylindrical roller and linear grove roller. This roller shape produced lowest damaging rate. Test results of the efficacy of preprocessing showed that the air spraying after preprocessing produced highest performance. The rotational speed and inclination of the roller didn't affect the bract removing performance. Optimum injection angle of the air jet nozzle was $70^{\circ}$. To increase bract removing rate and to reduce corn damage, required injection pressure and injection nozzle diameter were decided to less than 0.4 MPa and 2.5 mm, respectively. More than 3 times of nozzle passing produced good bract removing performance and there were no significant difference between the number of passing times.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.3 no.1
• /
• pp.132-141
• /
• 2001

This study was conducted to determine effects of whole and processed corns on attachment characteristics of rumen microbes in Hanwoo. Whole corn(WC) was processed into four different types; ground corn(GC), cracked corn(CC), flaked corn(FC), and soaked corn(SC). After each processed corns was incubated in the rumen of Hanwoo for 12 h and 24 h, attachment characteristics of rumen microbes and morphological changes of feed substrates was examined by utilizing scanning electron microscopy(SEM). In this study, the treatment group of GC and CC showed the highest in the attachment of rumen microbes. On the other hand, microbial attachments to the starch particle of WC and SC were hardly detected. However, with the increase of incubation time the surface of WC and SC was covered by many microbes, resulting in enhancing the surface degradation.

• Journal of Animal Science and Technology
• /
• v.45 no.3
• /
• pp.433-442
• /
• 2003

The objective of these studies were to examine the effects of processing methods of corn grains on in vitro dry matter digestability and in sacco degradability in the rumen by three ruminally cannulated dry Holstein cows. The corns for these experiments were untreated; whole corn L(density; 660 g/$\ell$), whole corn H(density; 740 g/$\ell$), and treated by four different types: Ground corn, 3.8 mm, 2.8 mm, and 1.5 mm flaked corns. The results obtained were summarized as follows: The DM degradabilities, after 48 hr incubation by in sacco method, were the highest(94.4, 88.0 and 87.0%, respectively) in 1.5 mm flaked corn, ground corn, and 2.8 mm flaked corn. The 3.8 mm flaked corn was degraded significantly lower than these. Until 12 hr incubation, whole corn L tended to be degraded little more than whole corn H, was not significantly different. However, after 24 hr incubation, the significant differences between whole corn L and whole corn H were shown(P<0.05). The DM digestabilities by in vitro digestion were the highest for 1.5 mm flaked corn and ground corn(92.3 and 91.2%, respectively)(P<0.05), followed by 2.8 mm and 3.8 mm flaked corn(83.9 and 83.4%, respectively), tended to be similar to those by in sacco method. Whole corn L was digested twice more rapidly than whole corn H. Summarizing the experimental data, compared with unprocessed corns, the flaked corns were significantly increased in the degradabilities of dry matter in the rumen. In addition, as increasing the flaking degree of corn, the degradabilities of dry matter were significantly improved. Referring to these kinds of physical characteristics of grain sources in the ruminal degradabilities, it is believed to be possible to optimize the environment of the fermentation in the rumen.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.47
• /
• pp.107-123
• /
• 2002

This paper is intented to present a information of various aspects of quality related characteristics and standards for grades in maize. Maize is world's one of the three most popular cereal crops and a primary energy supplement and can contribute up to 30, 60, and 98% of the dairy diet's protein, net energy, and starch, respectively. Maize is also processed into industrial goods by wet or dry milling. Sweet corn is a leader among vegetable crops and its production for fresh or processing markets is a major industry in many countries. Over the years, the combined efforts of breeders and geneticists, biochemists, food scientists, and others have helped bring us to the point where we understand issues related to sweet corn quality. Traditional criteria for selecting corn hybrids have been based primarily on agronomic factors, including grain production, disease resistance, drought tolerance, and storage characteristics. Little emphasis has been placed on the quality and nutritional values of corn. Although there is widespread interest for value-enhanced corns have increased tremendously in the last five years, there is limited information available on the production and comparing the quality attributes of specialty grains with those of normal yellow dent corn. Most countries have developed national maize standards, aiming to provide a framework for trade, both internal and external. Where trading involves direct choice and price negotiation in front of the commodity, grading standards are rarely employed; quality is assessed visually and is influenced by end-use, and the price is determined more by local rather than national factors. The use of an agreed standard will provide an unambiguous description of the quality of the consignment and assist in the formation of a legally-binding contract. Standards can also be seen to protect consumers rights through setting limits to the amount of unsuitable or noxious material.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.3 no.1
• /
• pp.116-131
• /
• 2001

Experiments were conducted to determine effects of whole and processed corns on in situ disappearance rates of nutrients in the rumen and in vitro degradability of dry matter by rumen microorganisms. Whole corn(WC) was processed into four different types; ground corn(GC), cracked corn(CC), flaked corn(FC), and soaked corn(SC). In the in situ experiment, the rate of ruminal DM disappearance after 48 hour incubation was highest in GC(76.1%) and lowest in WC and SC(12% ; P<0.01). The rate of ruminal CP disappearance after 48 hour incubation was highest in GC and CC(48 and 38%, respectively; P<0.01). The rate of ruminal OM disappearance after 48 hour incubation was highest in GC(76.14%) and lowest in WC and SC(11.82 and 12.26%, respectively; P<0.01). In the in vitro experiment, the two-stage incubation technique was used to measure digestibilities of whole and processed corns. The digestibility of DM was higher in GC, CC and FC(86.95, 85.84 and 82.29%, respectively) than in WC(15.36%; P<0.01).