Article pubs.acs.org/JAFC
Correlating Molecular Spectroscopy and Molecular Chemometrics to Explore Carbohydrate Functional Groups and Utilization of Coproducts from Biofuel and Biobrewing Processing Limei Chen,†,‡ Xuewei Zhang,*,† and Peiqiang Yu*,†,‡ †
College of Animal Science and Animal Veterinary, Tianjin Agricultural University, 22 Jinjin Road, Tianjin 300384, China Ministry of Agriculture Strategic Research Chair Program, Department of Animal and Poultry Science, College of Agriculture and Bioresources, University of Saskatchewan, 51 Campus Drive, Saskatoon, S7N 5A8 Saskatchewan, Canada
‡
ABSTRACT: Dried distillers grains with solubles (DDGS) was coproducts from bioethanol and biobrewing industry. It was an excellent resource of protein and energy feedstuff in China. Conventional studies often focus on traditional nutritional profiles. To data, there is little research on molecular structure-nutrition interaction of carbohydrate in coproducts. In this study, five kinds of corn-grain based DDGS and two kinds of barley-grain based DDGS were collected from different manufactures in the north of China. They were coded as “1, 2, 3, 4, 5, 6, and 7”, respectively. The primary purposes of this project were to investigate the molecular structure-nutrition interaction of carbohydrate in coproducts, in terms of (1) carbohydrate-related chemical composition and nutrient profiles, (2) predicted values for energy in coproducts for animal, and (3) in situ digestion of dry matter. The result showed that acid detergent fiber content in corn DDGS and barley DDGS had negative correlation with structural carbohydrate peak area, cellulose compounds, and carbohydrate component peaks (first, second, and total peak area), which were measured with molecular spectroscopy. The correlation between carbohydrate peak area (second and total) and digestible fiber (tdNDF) were negative. There were no correlation between carbohydrate spectral intensities and energy values, carbohydrate subfractions partitioned by CNCPS system, and in situ rumen degradation. The results indicate that carbohydrate spectral profiles (functional groups) are associated with the carbohydrate nutritive values in coproducts from biofuel and biobrewing processing. KEYWORDS: cereal grain coproducts, carbohydrate nutritional values, molecular spectral features, carbohydrate molecular structure, functional group
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INTRODUCTION In recent years, dry distiller grains with solubles (DDGS) have become a new type of protein and energy feedstuff in animal industry in China due to its high content of protein and energy. Especially in the recent five years, DDGS production remains stablely increasing, as affected by in-depth processing policy. The more understanding of the nutritional values of DDGS means the more efficient utilization of DDGS. Also, it is a vital factor for accurate ration formulation. Previous studies often focus on conventional “wet” chemical analysis. The data are applied to estimate feed nutrient values in animals.1−5 However, although the feedstuff has the same chemical composition, there may appear a phenomenon of different utilization and availability. This may due to the traditional “wet” chemical analysis only takes total feed composition and total content into account without thinking about the feedstuff’s inherent structure, which is fully destroyed during lab digestion in chemical analysis.6 Recent unique studies in our team have been focusing on feed carbohydrate molecular structure and their interaction with nutritional values. The previous study indicated the interaction of carbohydrate structure with © 2014 American Chemical Society
bioavailability of nutrients in the digestive tract (rumen and gastrointestinal tract). It has been reported that changes in carbohydrate molecular structure were sensitive to nutritional values.7−10 However, limited information is available on correlation with carbohydrate molecular structure and nutritional values for the coproducts from biofuel and biobrewing processing in China. The coproducts (DDGS) are different with conventional plant-based feed sources due to a series of complex procedures of processing, such as particle size reducing, drying, and fermenting. This study aimed to investigate the carbohydrate molecular structure−nutrition interaction in the coproducts from different types of energy feedstocks for biofuel and biobrewing processing in China, in terms of (1) the carbohydrate basic chemical profile, (2) truly digestible nutrient, (3) predicted value for energy in animals, and (4) in situ digestion of the coproducts. Therefore, it was Received: Revised: Accepted: Published: 5108
February 10, 2014 April 4, 2014 April 16, 2014 April 16, 2014 dx.doi.org/10.1021/jf500711p | J. Agric. Food Chem. 2014, 62, 5108−5117
1
2
3 917.6 50.9 949.1 82.6 427.6 196.7 21.2 230.9 175.4 18.9 517.8 46.00
415.2 125.8 18.4 289.4 107.4 30.0 597.9 57.09
5
896.6 57.4 942.6 65.9
4
46.11
638.5 214.2 79.4 424.2 134.9 14.4 562.8
927.5 44.2 955.9 150.0
6
56.89
450.6 154.2 23.9 296.3 130.3 62.9 619.0
943.2 59.7 940.3 35.0
7
barley DDGS coproducts from beermaking
0.859
1.73 1.76 1.60 1.75 3.12 1.14 1.75
0.17 0.20 0.20 1.5
SEM
