Physicochemical Changes of Heat-Treated Corn Grain Used in Ruminant Nutrition

Abstract

Cereal grain is processed using different combinations of heat, moisture, time, and mechanical action in order to improve its digestibility. The objective of the present research was to quantitatively represent the physicochemical properties of raw and processed starch using an in vitro methodology, as well as to describe the changes that occurred after heat treatment, such as pelleting, steam flaking, micronization, and extrusion of corn. Based on the obtained results, pelleting, steam flaking, and micronization can be considered as mild heat treatment methods, whereas extrusion proved to be a severe heat treatment method. Analysis of functional and pasting properties implied a possible interaction between the degraded components in the steam-flaked sample, as well as in the micronized sample, through to a lesser extent. Additionally, the occurrence of dextrins was noted after extrusion. The obtained results indicate the existence of significant differences in the physicochemical properties of corn starch depending on the heat treatment applied, which could possibly affect rumen starch degradation traits.

Effects of winged bean tuber (WBT) modified starches substituted for cassava chip in concentrate diets on rumen fermentation, nutrient utilization, and blood metabolites in Thai native beef cattle

“…Wang et al [20] reported that the steaming of sorghum in the diet expanded total intake, which may have been caused by the greater palatability of feed containing steam and enhanced ruminal fermentation by increased ruminal digestible starch (RDS). Furthermore, this processing impact makes starch a more accessible surface for both ruminal microbial and pancreatic enzymes, which is beneficial to microorganisms in their proliferation and may contribute to digestion in the rumen [21]. The result of this study revealed an increase in CP nutrient intake when replacing 10 to 30% of CSC with WBTS, compared to the unsubstituted group (0% of WBTS), possibly because of the higher CP content in WBTS compared to CSC [4].…”

“…This occurs due to the hydrolysis or melting of some cellulose and hemicellulose components on the surface when materials are exposed to high temperatures [23]. Consequently, this process has the potential to alter and increase the specific surface area of the feedstuff, thereby enhancing feed utilization and digestibility [21,22,24]. Yahaghi et al [25] demonstrated that replacing barley with steam-treated sorghum grain in lamb diets could lead to improved ruminal fermentation and fiber digestibility.…”

“…He et al [22] suggested that ruminants may benefit from a more effective source of energy supply if they were fed steam feedstuffs. It's probable that the steam-flaking process broke down the protein's disulfide bond and the starch's embedded structure, making the starch surface more palatable for ruminal microbial breakdown enzymes [20,21], hence enhancing the starch's ruminal degradability when fed at a replacement optimal level of 10 to 25% of concentrate, which improved the degradability of starch and ruminal fermentation in the rumen [7,21]. According to Qiao et al [31], steam-flaking cereal grains cause the concentration of C3 to rise while the ratio of C2 to C3 decreases.…”

Degradability of Vicia ervilia Grain Using In Situ and CNCPS Methods, and Model-Based Analysis of Its Ruminal Degradation

“…Similarly, Ljøkjel et al [22] found that heat treatment reduced the ruminal degradation of starch in both barley grain and pea grain. Srakaew et al [45] and Kokić et al [46] found that microorganisms have access to more starch in the rumen due to heat and moisture. The disorganization of the starch granules in the grain's endosperm and disruption of the protein matrix may be to blame for this problem.…”