IMPACT OF FEEDING DISTILLERS GRAINS ON BEEF TENDERNESS AND SENSORY TRAITS

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IMPACT OF FEEDING DISTILLERS GRAINS ON BEEF
TENDERNESS AND SENSORY TRAITS R.K. Gill, D.L.
Roeber, and A. DiCostanzo Department of Animal
Science, University of Minnesota, St. Paul

• OBJECTIVES
• To evaluate effects of feeding distillers grains
  on muscle color, overall appearance, and surface
  discoloration during simulated retail display of
  fresh beef steaks.
• To determine whether feeding distillers grains
  affects beef tenderness from strip loin steaks.
• To evaluate effects of distillers grain on
  consumer ratings of beef palatability of strip
  loin steaks.

• INTRODUCTION
• As production of distillers grains (DG)
  increases, discovering additional value will help
  promote their use.
• Beef-breed cattle have been evaluated in regards
  to performance, but the impact of DG on consumer
  acceptance of beef is unknown.
• Reports from Russia indicated that DG enhanced
  intra-and inter-muscular fat deposition (Paishev
  et al., 1985).
• Response (P lt 0.05) of lightness (L) values in
  rib steaks to feeding increasing concentrations
  of dry DG (DDG) was quadratic (Gordon et al.,
  2002).

MATERIALS METHODS

• Tenderness
• Steaks (2.54 cm thick) were cooked to an internal
  temperature of 70C (temperature was monitored
  using a thermocouple).
• Cores (1.25 cm) were removed parallel to the
  muscle fiber from each steak.
• Shear values were calculated by taking the mean
  peak shear force required to shear cores from
  each steak.
• Palatability
• Recruited 95 consumers.
• Steaks were cooked in the same manner as for
  shear force determination.
• Panelists judged 14 samples, one sample/treatment
  group from each experiment.
• Panelists rated samples for tenderness,
  juiciness, and flavor using a nine-point hedonic
  scale (1 dislike extremely, 9 like
  extremely).

• Strip Loin Collection
• Within study, strip loins were collected from
  each of four Holstein steers in each of four
  replicate pens (n16/treatment 45.7 and 66.6
  of steer in Exp. 1 and 2, respectively).
• From Exp. 1, dietary treatments evaluated
  consisted of feeding a whole corncorn silage
  diet with soybean meal (Control), 12.5 DDG plus
  urea, and 25 or 50 DDG or WDG (DM basis).
• From Exp. 2, dietary treatments consisted of
  feeding cracked corncorn silagehay diets with
  soybean meal (SBM) control or urea (Urea)
  control, 10, 20, or 40 DDG or WDG (DM basis).
• Aged for 13 d at 13C.
• Color Evaluation Under Simulated Retail Display
• Steak were over-wrapped and maintained in a
  cooler at 2C 1C, under lighting conditions
  recommended by AMSA (1991).
• Steaks were evaluated for color attributes
  (visually and with a HunterLab Miniscan XE
  spectrophotometer) at 12 h intervals.

• Statistical Analysis
• Pen was used as the experimental unit.
• Retail display data were analyzed using a
  repeated measures model in SAS.
• Shear force data were analyzed using the General
  Linear Models (GLM) procedure of SAS.
• Taste panel data were analyzed using the Mixed
  Model procedure of SAS.
• Means were separated using the least square means
  procedure (SAS, 2001) when effects were
  significant at P lt 0.05.

RESULTS

• Color Evaluation
• At 138 h (time at which 75 of the steaks in at
  least one treatment group were characterized as
  being moderately unacceptable), a lower (P lt
  0.05) percentage of steaks from steers fed 25
  WDG (Exp.1) were unacceptable in visual
  appearance (Figure 1). Also, steaks from this
  treatment group had higher a values (P lt 0.05)
  than those of steaks from other treatments,
  except for those of steers fed 12.5 DDG (Table
  1).
• At 138 h, a greater (P lt 0.05) percentage of
  steaks from steers fed either 40 DDG or 40 WDG
  (Exp. 2) were considered moderately
  unacceptable (Figure 1). Steaks from these
  treatments had a values (P gt 0.05) that were
  lower than those of steaks from steers fed either
  Control or 12.5 DG (Table 1).

• Palatability
• No differences (P gt 0.05) in tenderness,
  juiciness, or flavor attributes were detected in
  either experiment (Tables 2 and 3).

• Tenderness
• Feeding DG had no (P gt 0.05) effect on shear
  force values in Exp.1 or Exp. 2 (Figures 2 and 3).

CONCLUSION Feeding distillers grains to
dairy-beef steers had no adverse effects on meat
color, tenderness, or sensory traits.

• References
• American Meat Science Association. 1991.
  Guidelines for Meat Color Evaluation. National
  Live Stock and Meat Board. Chicago, IL.
• Gordon C.M., J.S. Drouillard, R.K. Phebus, K.A.
  Hachmeister, M.E. Dikeman, J.J. Higgins, and A.L.
  Reicks. 2002. The effect of Dakota Gold-brand
  dried distillers grains with solubles of varying
  levels on sensory and color characteristics of
  ribeye steaks. 2002 Cattlemen's Day. Report of
  Progress 890. Kansas State University. pp. 72-74.
• Paishev, S.T., A.A. Sherstennikov, and E.A.
  Levanova. 1985. Morphological composition of
  carcass and nutritive value of beef from young
  bulls fattened on distillery grains. PPKRS
  8794.
• Funding for this project provided by the Iowa
  Corn Promotion Board.