The South Dakota ethanol industry is rapidly expanding. As a direct result of this expansion it is expected that in excess of 500,000 tons of corn co-products will be available to livestock enterprises annually as a feed source. Processing methods are, in general terms, similar among dry milling ethanol plants. However, newer technology and small deviations of methods can alter the nutritive value of the co-products. Subsequently, diet formulations using general nutritive values may be inaccurate and cause production inefficiencies.  The objective of this research project was to characterize the composition and nutritive value of corn co-products produced from several dry milling ethanol plants in the upper Midwest

Holt, Simone M.

Pritchard, Robbi H.

English

Public Research Access Institutional Repository and Information Exchange

South Dakota State UniversityOpen PRAIRIE: Open Public Research Access InstitutionalRepository and Information ExchangeSouth Dakota Beef Report, 2004 Animal Science Reports2004Composition and Nutritive Value of Corn Co-Products from Dry Milling Ethanol PlantsSimone M. HoltSouth Dakota State UniversityRobbi H. PritchardSouth Dakota State UniversityFollow this and additional works at: http://openprairie.sdstate.edu/sd_beefreport_2004Part of the Animal Sciences CommonsThis Report is brought to you for free and open access by the Animal Science Reports at Open PRAIRIE: Open Public Research Access InstitutionalRepository and Information Exchange. It has been accepted for inclusion in South Dakota Beef Report, 2004 by an authorized administrator of OpenPRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For more information, please contactmichael.biondo@sdstate.edu.Recommended CitationHolt, Simone M. and Pritchard, Robbi H., "Composition and Nutritive Value of Corn Co-Products from Dry Milling Ethanol Plants"(2004). South Dakota Beef Report, 2004. Paper 2.http://openprairie.sdstate.edu/sd_beefreport_2004/2Composition and Nutritive Value of Corn Co-products From Dry Milling Ethanol Plants  Simone M. Holt1 and Robbi H. Pritchard2,3 Department of Animal and Range Sciences  BEEF 2004 – 01  Introduction 123The South Dakota ethanol industry is rapidly expanding.  As a direct result of this expansion it is expected that in excess of 500,000 tons of corn co-products will be available to livestock enterprises annually as a feed source.  Processing methods are, in general terms, similar among dry milling ethanol plants.  However, newer technology and small deviations of methods can alter the nutritive value of the co-products.  Subsequently, diet formulations using general nutritive values may be inaccurate and cause production inefficiencies.   The objective of this research project was to characterize the composition and nutritive value of corn co-products produced from several dry milling ethanol plants in the upper Midwest.  Materials and Methods  Four regional dry milling ethanol plants were used in this study.  Samples were collected during March, April and May 2002.  Each plant was sampled four times per day over four consecutive days.  Sampling times were approximately 0800, 1100, 1300 and 1700 h.   The type of co-product sampled from individual ethanol plants depended on products being produced during the sampling period (Table 1).  Samples were collected such that each sample was representative of co-product received by producers.  To achieve this, in most instances, co-products were sampled from the transport carrier instead of the production stream or storage facilities.    During each 4 d sampling period, samples were refrigerated at each plant.  At the conclusion of                                                  1 Post Doctorate 2 Professor 3 The authors thank the SD Corn Utilization Council for their financial support of this research. the sampling period, samples were then transported to the South Dakota State University Ruminant Nutrition Laboratory for processing and analyses.    Proximate analysis, with the exception of the soluble samples, was assayed as individual samples.  The four samples of solubles collected on a given day from each plant were combined to form a single composite sample for each of the four days.   Composite soluble samples for each plant, and a similar composite of Wet Distiller’s Grains with solubles (WDGS) and Dry Distiller’s Grains with solubles (DDGS) were assayed for mineral concentrations at Oscar E. Olson Biochemistry Laboratories, South Dakota State University.  Laboratory assays performed on all samples are presented in Table 2.  Soluble samples were lyophilized using a commercial freeze drier (Labonco Lyph Lock 12, Labonco Corporation, Kansas City, MO).  NDF, ADF and ADIN assays were not determined on the soluble samples.  ADIN was determined only on DDGS and WDGS from two plants where fiber results suggested possible differences in heat damage to the co-product.  These samples were composited for each plant by day.  Levels of ADIN were reported on a crude protein basis (ADIN-CP) and as a proportion (%) of the total crude protein in the sample (ADFIP).  Statistical analyses were conducted using the GLM procedures of SAS (1999) with day and plant included as the independent variables in the model.  Treatment means were compared using least significant differences (P < 0.05).  Across plants, variability was tested for homogeneity of variance.  Within plant variation was evaluated by univariate analysis (SAS, 1999).       1Results and Discussion  Mean nutrient compositions of traditional co-products assayed across all plants are presented in Table 3 and compared to NRC tabular values.  Corn is generally the commodity that is replaced when corn co-products are added to a diet.    Cracked corn grain has smaller standard deviations for most components than the DDGS and WDGS sampled during this study (Table 3).  These results suggest that diet formulation consistency may be an issue when using these products.      Nutrient composition of Modified dry distiller’s grains, Blended dry distiller’s grains and Solubles are presented in Table 4.  Although the Modified and Blended DGS products are produced by different processes they are often considered interchangeable feed sources.  Based upon this survey, the Modified product was much lower in CP and fiber and much higher in fat than the Blended product.  Variability in proximate composition was much greater with the Modified DGS.    Dry matter content of Soluble samples were approximately 7 percentage points lower than most plants suggested (Table 4).  This deviation would alter the value of solubles by 25 to 30%.    A small amount of variation in dry matter content was reported in DDGS between plants (P < 0.05; Table 5).  Greater differences were observed between plants for dry matter content of WDGS (P < 0.05).  The amount of solubles that is utilized in these products from plant to plant, in particular WDGS, may be a potential cause of the variation that exists.    A significant day effect within plant was reported for crude fat content for Plant C, and neutral detergent fiber for Plant D (Table 6).  While these differences between days were statistically significant, the magnitude of change was of little biological consequence.  The resultant low variation in composition within a day reflects good manufacturing controls in the plants sampled in this study.  Neutral detergent fiber content differed (P < 0.05) among all plants (Table 6), and was lowest for Plant B (37.3%) and highest for Plant C (49.3%).  Heat damage of co-products was proposed as a possible explanation for the differences in NDF since there was no apparent dilution of CP or fat associated with differences in NDF.  Acid detergent insoluble nitrogen (ADIN) assays were conducted on DDGS and WDGS composites for Plants B and C to ascertain if heat damage would explain differences in the NDF content (Table 7).  ADIN is the nitrogen remaining in the ADF residue.  While some occurs naturally in all plant material, it is generally considered to be an estimate of heat damage occurring during storage or processing (Goering and Van Soest, 1970) and would contribute to the NDF residue mass.  The ADIN content from DDGS and WDGS did not differ (P > 0.05) when expressed as a proportion of DM (ADIN-CP) or as a proportion of total crude protein (ADFIP).  Similar ADFIP content for both these co-products indicates that both plants were able to dry distiller’s grains without causing the Malliard reactions that reduce crude protein availability.  A possible explanation is that there are differences in starch content of the co-products from these two plants.    Composite samples of DDGS, WDGS and Solubles were assayed for selected mineral concentrations and compared to NRC tabular values (Table 8).  In general, for the DDGS samples, the mineral concentrations were lower than those reported by the NRC.  Iron concentrations, on average, were only approximately 22% of those reported by the NRC.  Sodium and sulfur levels in DDGS were highly variable.  Similar to what was observed for DDGS, mineral concentrations for WDGS as a whole were lower than the NRC tabular values.  Iron levels were variable between plants, ranging from approximately 21 to 153% of those reported in the NRC.  Although concentrations of phosphorus were lower (5.7-20.0%) than reported values (NRC, 2000), variation existed between plants.    Sodium and potassium levels were also highly variable and in some instances differed substantially from NRC values.  Mineral content of solubles tended to be closer to tabular values although substantial variations were present.  These deviations were sufficient to be of critical importance if feeding solubles to cattle.     2Conclusion  Deviations in composition of ethanol co-products from tabular values can be partially explained by recent advances in technology that have improved the fermentation process and reduced residual starch.  As a consequence, remaining nutrient and non-nutrient components in the co-products have increased.  However, this did not apply to the minerals evaluated.  As the renewable fuels industry continues to expand and develop new technologies, it is important to understand these changes and their impact on livestock industries.  Monitoring these changes will need to continue at some level to assure efficient utilization of these co-products as livestock feeds.     3Tables Table 1.  Type of corn by-products samples Product Type Description DDGS Dry distiller’s grains with solubles   Modified DGS Dry distiller’s grains with additional solubles added back to the original product (MDGS)   Blended DGS Dry distiller’s grains with solubles are blended with Wet distiller’s grains with solubles (BDGS)   WDGS Wet distiller’s grains with solubles   Solubles Concentrated solubles that remain after post-fermentation separations.   Table 2.  Laboratory assays Assay Method Dry Matter (DM) 100o C oven, AOAC Official Method 034.01   Crude Protein (CP) Kjeldahl Method, AOAC Official Method 954.01   Neutral Detergent  Analysis on samples dried at 55o C.  Goering, H.K. and  Fiber (NDF) P. J. Van Soest  1970.  In: Forage Fiber Analyses.   (USDA, Agric. Handbk. No. 379 Jacket No. 387-598)   Acid Detergent  Analysis on samples dried at 55o C.  Goering, H. K. and  Fiber (ADF) P. J. Van Soest.  1970.  In: Forage Fiber Analyses.   (USDA, Agric. Handbk. No. 379 Jacket No. 387-598)   Acid Detergent Insoluble  NFTA 1993.  Forage Analyses Procedure - Method 6. Nitrogen (ADIN)    Ash (ASH) 600o C Muffle Furnace, AOAC Official Method 942.05   Ether Extract – Crude Fat   Soxhlet Fat Extraction Methods, AOAC (FAT)    Minerals   Iron (Fe), Magnesium(Mg), Flame Atomic Absorption, AOAC Official Method 965.09A Phosphorus (P),   Potassium (K), Sodium (Na),  Sulfur (S)   4 Table 3.  Comparison of NRCa tabular values of cracked corn grain, dry distiller’s grain with solubles (DDGS) and wet distiller’s grain with solubles (WDGS) to values determined during this study  Cracked corn grain  DDGS  WDGS Item, % NRC Std dev  NRC Study Std dev  NRC Study Std dev DM 90 0.88 91 90.0 1.08 25 31.4 2.12 CP 9.8 1.06 29.5 33.3 2.78 29.7 35.5 1.37 NDF 10.8 3.57 46 42.7 5.17 40 42.3 6.34 ADF 3.3 1.83 n/a 13.2 2.51 n/a 12.1 2.46 Ash 1.5 0.33 5.2 4.1 0.28 5.2 3.8 0.63 Fat 4.1 0.64 10.3 13.1 1.95 9.9 12.1 1.39 aNRC Beef Cattle (Update 2000).  Table 4.  Mean nutrient composition of modified DDGS, blended DDGS and solubles  Modified DDGS  Blended DDGS  Solubles Item, % Mean Std dev  Mean Std dev  Mean Std dev DM 58.9 2.79 50.5 0.75 23.4 2.87 CP 29.7 1.44 36.4 0.07 19.8 2.54 NDF 34.9 2.03 49.1 0.34   ADF 10.9 1.87 14.6 0.22   Ash 5.3 0.42 3.6 0.03 9.5 0.99 Fat 16.7 1.24 10.6 0.17 32.1 1.90  Table 5.  Nutrient composition of DDGS and WDGS by plant Dry Distiller's Grain with Solubles    Item, % Plant A Plant B Plant C Plant D SEM  DM 90.91a 89.80bc 90.48ab 89.39c 0.260  CP 33.16b 34.03b 36.71a 30.68c 0.513  NDF 40.29c 37.34d 48.91a 45.30b 0.720  ADF 14.04b 10.94c 16.00a 12.85b 0.476  ASH 4.20a 4.23a 3.88b 4.08ab 0.074  FAT 13.52a 13.39a 10.35b 14.20a 0.401         Wet Distiller's Grain with Solubles    Item, % Plant A Plant B Plant C SEM   DM 36.48a 32.86b 29.52c 0.277   CP 36.18a 34.39b 36.58a 0.246   NDF 46.44a 36.10b 48.18a 0.511   ADF 16.93a 9.81c 14.05b 0.263   ASH 2.75b 4.23a 3.47ab 0.153   FAT 12.49ab 13.12a 11.04b 0.298    abc Means within a row without common superscripts differ (P < 0.05).  5 Table 6.  Mean daily NDF, ADF and FAT composition of dry distiller's grains with solubles NDF      Day Plant A Plant B Plant C Plant D 1 40.55 36.37 50.84 48.78a2 39.09 38.61 48.35 45.66b3 42.95 36.89 47.3 44.64bc4 39.87 37.48 49.65 42.12cMean 40.29x 37.34w 48.91z 45.3yEMS 5.895 6.872 7.129 3.158      ADF      Day Plant A Plant B Plant C Plant D 1 14.36 10.87 16.61 13.94 2 15.19 10.34 16.11 13.38 3 12.36 11.08 15.65 11.19 4 14.49 11.45 14.91 12.89 Mean 14.17x 10.94w 16.1y 12.85xEMS 2.136 1.537 2.148 5.905      FAT      Day Plant A Plant B Plant C Plant D 1 12.8 13.21 11.03a 13.76 2 14.32 13.56 10.76a 14.54 3 14.29 14.4 9.58ab 14.29 4 13.46 12.41 8.47b 14.22 Mean 13.46x 13.39x 10.41w 14.2wEMS 0.672 3.922 0.439 2.304 a,b,c Day means within plant without common superscripts differ (P < 0.05). w,x,y,z Plant means without common superscripts differ (P < 0.05).   6 Table 7.  Acid detergent insoluble nitrogen (%) for dry distiller’s grain with solubles and wet distiller’s grain with solubles.  Dry Distiller’s Grain with Solubles Plant B  Plant C Day CP ADIN-CPa ADFIPb  CP ADIN-CPa ADFIPb1 34.1 4.1 12.1  35.0 3.2 9.1 2 33.4 3.2 9.6  36.3 2.5 6.9 3 34.8 3.6 10.2  41.3 3.6 8.6 4 33.9 2.8 8.3  34.7     n/a     n/a Mean 34.0 3.4 10.1  36.6 3.0 8.2         Wet Distiller’s Grain with Solubles Plant B  Plant C Day CP ADIN-CPa ADFIPb  CP ADIN-CPa ADFIPb1 33.7 3.8 11.1  36.3 6.0 16.5 2 34.3 2.7 7.9  37.5 3.3 8.8 3 34.9 2.8 7.9  36.4 2.9 8.0 4 34.7 3.1 9.0  36.1 3.3 9.0 Mean 34.4 3.1 9.0  36.6 3.9 10.6 aAcid detergent insoluble nitrogen expressed as crude protein, %. bAcid detergent insoluble N as a percentage of total N.  Table 8.  Selected mineral concentrations for DDGS, WDGS and solubles composited by plant DDGS  NRC Plant A Plant B Plant C Plant D Iron, ppm 560 110 154 130 102 Magnesium, % 0.33 0.32 0.32 0.259 0.317 Phosphorus, % 0.83 0.722 0.778 0.664 0.783 Potassium, % 1.07 0.938 0.986 0.76 0.947 Sodium, % 0.24 0.172 0.0545 0.214 0.138 Sulfur, % 0.4 0.504 0.368 0.353 0.692       WDGS        NRC Plant A Plant B Plant C  Iron, ppm 560 118 660 857  Magnesium, % 0.65 0.204 0.311 0.2  Phosphorus, % 1.4 0.484 0.754 0.53  Potassium, % 1.83 0.412 0.933 0.54  Sodium, % 0.24 0.041 0.054 0.162  Sulfur, % 0.4 0.394 0.36 0.376        SOLUBLES        Plant A Plant B Plant C Plant D  Iron, ppm 105 212 249 143  Magnesium, % 0.71 0.639 0.774 0.759  Phosphorus, % 1.49 1.42 1.65 1.58  Potassium, % 2.5 2 2.28 2.3  Sodium, % 0.302 0.118 0.692 0.436  Sulfur, % 0.337 0.254 0.32 1.15     7

Composition and Nutritive Value of Corn Co-Products from Dry Milling Ethanol Plants

https://openprairie.sdstate.edu/cgi/viewcontent.cgi?article=1001&amp;context=sd_beefreport_2004

Composition and Nutritive Value of Corn Co-Products from Dry Milling Ethanol Plants

Abstract

Similar works

Full text

Available Versions

Public Research Access Institutional Repository and Information Exchange