Optimization of the Effect of Pineapple By-Products Enhanced in Bromelain by Hydrostatic Pressure on the Texture and Overall Quality of Silverside Beef Cut

Abstract

Dehydrated pineapple by-products enriched in bromelain using a hydrostatic pressure treatment (225 MPa, 8.5 min) were added in marinades to improve beef properties. The steaks from the silverside cut (2 ± 0.5 cm thickness and weight 270 ± 50 g), characterized as harder and cheaper, were immersed in marinades that were added to dehydrated and pressurized pineapple by-products that corresponded to a bromelain concentration of 0-20 mg tyrosine, 100 g^-1 meat, and 0-24 h time, according to the central composite factorial design matrix. Samples were characterized in terms of marination yield, pH, color, and histology. Subsequently, samples were cooked in a water-bath (80 °C, 15 min), stabilized (4 °C, 24 h), and measured for cooking loss, pH, color, hardness, and histology. Marinades (12-24 h) and bromelain concentration (10-20 mg tyrosine.100 g^-1 meat) reduced pH and hardness, increased marination yield, and resulted in a lighter color. Although refrigeration was not an optimal temperature for bromelain activity, meat hardness decreased (41%). Thus, the use of pineapple by-products in brine allowed for the valorization of lower commercial value steak cuts.

Keywords: bromelain; enzyme activity; hydrostatic pressure; marinade; meat; pineapple by-products; texture.

Figure 1

Effect of marinades on pH as a function of bromelain concentration (mg tyrosine.100 g⁻¹ meat) and time (h). Response surfaces fitted to pH of brine (a) and pH of marinated steak (b).

Figure 2

Effect of marinades on marination yield of the steaks as a function of marinades: bromelain concentration (mg tyrosine.100 g⁻¹ meat) and time (h).

Figure 3

Response surfaces fitted for color parameters in marinated steaks: parameter ΔL* (a), parameter Δa* (c), and parameter ΔL*in cooked steaks (b).

Figure 3

Response surfaces fitted for color parameters in marinated steaks: parameter ΔL* (a), parameter Δa* (c), and parameter ΔL*in cooked steaks (b).

Figure 4

Response surface fitted for hardness as a function of marinades (bromelain concentration (mg tyrosine.100 g⁻¹ meat) and time (h)).

Figure 5

Study of the effect of adding brine on marinated steaks: (a) pH, (b) ΔL* color, (c) Δa* color, and (d) hardness. Error bars represent ± standard deviation (pH and color: n = 3 and hardness: n = 20). pH: Different letters express significant differences between pH marinated steak samples (lower case letters); between pH brine samples (upper case letters); and between pH cooked steak samples (bold lower-case letters). Color: Different letters express significant differences between color marinated steak samples (lower case letters) or between color cooked steak samples (upper case letters).