Effects of natural colourants and pulsed electric field technology on the quality parameters of nitrite-free bacon

Replacement of nitrites in cured meat products, such as bacon chops, challenges maintaining the characteristic pink colour and other quality attributes. This study evaluates the effectiveness of natural colourants: betanin, red yeast (Monascus) rice extract, and roselle (Hibiscus sabdariffa) extract, as alternatives to nitrites for colour enhancement in nitrite-free bacon. Pulsed electric field (PEF) pre-treatment was applied to samples before immersing them in brine with colourant. Bacon loins were treated with brines containing different concentrations of these colourants, then vacuum packaged, tumbled, and stored at 4°C until further testing. Instrumental colour parameters (L*, a*, b*, hue angle, chroma, and cured colour ratio) were measured for both uncooked and cooked samples. Results showed that uncooked bacon treated with 0.05% betanin exhibited similar redness (a*) and cured colour ratios to nitrite-treated controls, indicating that betanin has the potential as a feasible colourant. Red yeast rice extract at 0.10% also enhanced redness but increased yellowness (b*), affecting the overall colour. Upon cooking, a* values of colorant-treated bacon were comparable with the nitrite-treated sample. However, they all displayed significantly (P<0.05) higher b*, hue angle, and chroma values, and decreased L* and cured colour ratio values. While the applied PEF treatment did not affect the instrumental colour of the uncooked and cooked samples, it was beneficial for reducing lipid oxidation on uncooked bacon with betanin and roselle extracts. These findings suggest that while natural colourants can mimic the colour effects of nitrites in uncooked bacon, additional strategies are required to improve colour stability.</jats:p>