Expression of fat deposition and fat removal genes is associated with intramuscular fat content in longissimus dorsi muscle of Korean cattle steers

Intramuscular fat (IMF) in cattle is an important component of traits that influence meat quality. We measured carcass characteristics and gene expression in Korean steers to clarify the molecular mechanism(s) underlying IMF deposition in LM tissue by determining the correlation between IMF content and gene expression abundance and by developing models to predict IMF content using gene expression abundance. The deposition of IMF is determined by a balance between fat deposition and fat removal in the LM. We measured mRNA abundance of lipid metabolic genes including lipogenesis [acetyl CoA carboxylase (ACC), fatty acid synthase (FASN)], fatty lipid uptake [lipoprotein lipase (LPL), fatty acid translocase (CD36), fatty acid transport protein 1 (FATP1)], fatty acid esterification [glycerol-3-phosphate acyltransferase 1 (GPAT1), acylglycerol phosphate acyltransferase 1 (AGPAT1), diacylglycerol acyltransferase 1 (DGAT1), DGAT2], lipolysis [adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL), monoglyceride lipase (MGL)], and fatty acid oxidation [carnitine palmitoyl transferase 1B, very long-chain acyl-CoA dehydrogenase (VLCAD), medium-chain acyl-CoA dehydrogenase (MCAD)] in the LM. The mRNA abundance of the GPAT1 gene showed the greatest correlation (r = 0.74; P < 0.001) with IMF content among 9 fat deposition genes. The gene expression abundance of other fat deposition genes including ACC, FASN, LPL, CD36, FATP1, AGPAT1, DGAT1, and DGAT2 also exhibited significant positive correlations (P < 0.05) with IMF content in the LM. Conversely, ATGL mRNA abundance showed the greatest negative correlation (r = -0.68; P < 0.001) with IMF content in the LM among 6 fat removal genes. The expression of other fat removal genes including MGL, VLCAD, and MCAD showed significant negative correlations (P < 0.05) with IMF content. Our findings show that the combined effects of increases in lipogenesis, fatty acid uptake, fatty acid esterification, and of decreases in lipolysis and fatty acid oxidation contribute to increasing IMF deposition in Korean steers. The multiple regression analysis revealed that the mRNA abundance of the GPAT1 gene in the LM was the first major variable predicting IMF content (54%) among 15 lipid metabolic genes. The second was mRNA abundance of ATGL (11%). In conclusion, these results suggest that GPAT1 and ATGL genes could be used as genetic markers to predict IMF deposition in the LM.     

Effects of Chemical Functionalization of MWCNTs on the Structural and Physical Properties of Elastomeric Copolyetherester-based Composite Fibers

Elastomeric copolyetherester (CPEE)-based composite fibers incorporating various neat and functionalized multiwalled carbon nanotubes (MWCNTs) were prepared through a conventional wet-spinning and coagulation process. The influence of functionalized MWCNTs on the morphological features, and the thermal, mechanical properties and electrical conductivity of CPEE/MWCNT (80/20, w/w) composite fibers were investigated. FE-SEM images show that a composite fiber containing poly(ethylene glycol)-functionalized MWCNTs (MWCNT-PEG) has a relatively smooth surface owing to the good dispersion of MWCNT-PEGs within the fiber, whereas composite fibers including pristine MWCNTs (p-MWCNT), acid-functionalized MWCNTs (a-MWCNT), and ethylene glycol-modified MWCNTs (MWCNT-EG) have quite a rough surface morphology owing to the presence of MWCNT aggregates. As a result, the CPEE/MWCNT-PEG composite fiber exhibits noticeably increased thermal and tensile mechanical properties as well as a faster crystallization behavior, which stems from an enhanced interfacial interaction between the CPEE matrix and MWCNT-PEGs.     

Flour Characteristics Related to Optimum Water Absorption of Noodle Dough for Making White Salted Noodles

Physicochemical properties of 34 wheat flours with various classes and different protein contents were related to optimum water absorption of noodle dough. Club and soft wheat flours generally exhibited higher water absorption (34–37%) of noodle dough than hard wheat flours (31–35%). Optimum water absorption of noodle dough in three hard wheat flours with five different protein contents was 33–37%. Optimum water absorption was negatively correlated with flour protein content and SDS sedimentation volume. Physical properties of flour, damaged starch content, NIRS hardness and water retention capacity, influenced optimum water absorption of noodle dough from club, soft and hard wheat flours. A prediction equation developed using protein content, water retention capacity and SDS sedimentation volume of flour provides a reliable estimation of the optimum absorption of noodle dough for making noodles.     

Composition,Microstructure, Water Imbibition,and Thermal Properties of Abraded Barley

Barley, nonwaxy hull (cvs. Crystal and Meltan) and waxy hull-less (cvs. Merlin and Waxbar), was abraded at 10, 20, and 40% of kernel weight on a laboratory scale and commercially abraded at two levels: fine and coarse. In 40% abraded kernels of Crystal, protein, ash, and free lipids contents decreased by 1.6, 1.4, and 1.4%, respectively, and starch and β-glucans contents increased by 16 and 1.2%, respectively, compared to nonabraded kernels. Merlin showed smaller changes in the levels of these components, except for proteins. Changes in starch and protein in laboratory abraded barley were used to estimate the level of barley abrasion on a commercial scale. Scanning electron microscope pictures revealed that in nonwaxy barley at 10% abrasion the hull and part of the seed coat were absent, whereas waxy barley lost all of the seed coat and most of the aleurone layer. Maximum water imbibition of 40% abraded waxy barley was reached after 5 hr of soaking, whereas nonwaxy barley needed 8 hr to level off. Nonwaxy barley kernels at 20% abrasion and cooked for 10 min required 52 N to compress to 50% thickness, whereas waxy barley needed only 28 N. Changes in chemical composition and microstructure due to abrasion had a strong effect on the thermal properties of kernels during cooking. The extent to which barley starch was gelatinized during cooking was evaluated by differential scanning calorimetry. Crystal and Merlin showed significant decreases in enthalpy value for 40% compared to 10% abraded barley. These results indicate that when a large portion of the outer layer of barley is removed, water and heat penetrate more quickly into kernels during cooking, causing more starch to be gelatinized. The results obtained in this study indicate that changes in composition and microstructure due to abrasion affect the rate of water imbibition, hardness of cooked kernels, and enthalpy value of starch. Composition and properties of laboratory abraded barley could be used to predict the level of abrasion and properties of barley abraded on a commercial scale within the same cultivar.     

Wet Fractionation of Garbanzo Bean and Pea Flours

Garbanzo bean and pea flours originating from the central part of the cotyledons were higher in starch but lower in protein and fiber than those from the outer layer of the cotyledon. These flours were fractionated by the wet process into prime starch, tailing starch, and solubles. The patented wet-fractionation method was successfully modified to reduce the total amount of water during the process. The modified process produced comparable yield and purity of separated fractions. Under the recycling water method, the yields of prime starch were 46.7, 33.6, and 41.1%, respectively, in garbanzo bean and two smooth pea cultivars (Latah and SS Alaska). Isolated prime starches were <0.4% in protein and <0.19% in ash, indicating high purity.     

Microstructure of Seeds,Flours, and Starches of Legumes

The microstructure of cotyledons and flours of both garbanzo beans and peas were examined by a scanning electron microscope (SEM) at low and high magnification. While the cells in the outer layer of the cotyledon were elongated and tightly packed in both garbanzo beans and peas, they were rounder and more loosely packed in the central part of the cotyledon, with many intercellular spaces. Cotyledon cells of garbanzo beans were smaller than those of the pea cultivars. Flour fractions from the inner layer of the cotyledon of garbanzo beans and pea cultivars had much finer particles; were lower in protein, lipid, ash and fiber; and contained more starch than those from the outer layer of the cotyledon. In prime starches isolated from garbanzo beans and smooth peas, protein, free lipid, and ash were lower than 0.41, 0.11, and 0.17%, respectively, indicating that the starches are highly pure. Garbanzo bean starch had smaller and smoother granules than those of smooth peas. Starch granules of wrinkled pea cv. Scout had a unique shape, with deep fissures and grooves, which could be partly responsible for difficulties encountered during the wet fractionation process.     

Genotypic Variation in Color and Discoloration Potential of Barley‐Based Food Products

Barley has a variety of potential food uses. However, the dark gray color of the final products negatively affects consumer acceptability. We determined the discoloration potential of barley from different classes and genotypes, and evaluated the relationship of barley composition, total polyphenol content, and polyphenol oxidase (PPO) activity with discoloration potential of barley. Barley grains were abraded, milled into flour, and analyzed for composition, total polyphenol content, and PPO activity. Total polyphenol content of abraded barley, expressed as gallic acid %, was lowest in hulled proanthocyanidin‐free barley (0.02–0.04%), followed by hulled proanthocyanidin‐containing barley (0.11–0.18%), and hull‐less barley (0.19–0.26%). PPO activity of abraded kernels ranged from 62.1 units/g in hulled proanthocyanidin‐containing Baronesse to 116.5 units/g in hulled proanthocyanidin‐free CA803803. Dough sheet brightness (L* value) was the best indicator of discoloration potential of barley. Large variation in L* value of dough sheets was observed among different classes and among genotypes within classes. Brightness of dough sheets measured at 24 hr were significantly higher in hulled (65.3–78.1) than in hull‐less (59.0–63.9) barley, and within hulled barley, higher in proanthocyanidin‐free (72.2–78.1) than in proanthocyanidin‐containing (65.3–69.6) barley. Total polyphenol content significantly correlated with the discoloration potential of barley. Protein content and ash content also had a significant negative correlation with discoloration of dough sheets. The results indicated that polyphenol compounds may play a major role in discoloration potential of barley‐based products.