Abstract
Clean labelling refers to consumers’ desire for manufacturers to be more transparent in the way their products are made and sourced. Natural antioxidants (spices, herbs, fruits, or vegetables) have been proven to offer the same functionality as their synthetic counterparts, with the advantage of being label friendly and process compatible, maintaining meat quality and reducing food waste. Lamb meat has the challenges to have an intense flavour and fat composition to test the effectiveness of some of these natural antioxidants like hydroxytyrosol (HXT). The current paper was designed to test both natural (HXTo) and synthetic (HXTs) antioxidants using four lamb patty batches: one Control (C) (which included sulphites); a reference (R) sample (14.6% carnosic acid and 6% carnosol from natural rosemary extracts, 200 ppm); a sample containing synthetic hydroxytyrosol (HXTs, 99% purity, 200 ppm); and a sample with added organic hydroxytyrosol (HXTo, sample 7% purity from olive tree leaves, 200 ppm). A shelf-life study was carried out for 6 days at 4 °C, testing proximal composition and mineral bioavailability, pH changes, colour (by CIELab), total antioxidant capacity (TAC by oxygen radical absorbance capacity (ORAC)), lipid and protein oxidation (thiobarbituric acid reactive substances (TBARs) and thiol loss, respectively), volatile compound profiles (by HPC-MS), sensory evaluation, and microbiological growth (as total vial count (TVC) and total coliform count (TCC)). Results revealed that lamb burgers with added HXTs had better-preserved raw lamb meat in the test conditions, with reduced colour losses, lipid oxidation, and release of volatile compounds, the half the microbiological growth (TVC) of the Control, the best TAC, and significantly increased (p < 0.05) minerals bioavailability, while maintaining sensory acceptability. In summary, natural antioxidants are an adequate strategy for lamb meat burgers. Regarding HXTo, obtained from olives, the synthetic analogue is even more effective in terms of preservative and antioxidant activity, and in maintaining the nutritional value, sensory characteristics, and safety of food products.
Highlights
Sheep were among the first livestock to be domesticated and used for their milk, wool, and meat.As early as the Neolithic age, from 9000 BCE, lambs were being raised in many parts of the Mediterranean and Central Asia
Natural antioxidant extracts were supplied by Nutrafur-Frutarom, S.A. (Alcantarilla, Murcia, Spain): organic hydroxytyrosol (HXTo), obtained from vegetation waters from olive trees (Olea europaea), containing 7.26% pure bioactive compound; and rosemary extract (Rosmarinus officinalis L.) (R), containing 14.59% carnosic acid, 5.84% carnosol, and 0.60% 12-O-methylcarnosic acid
The knowledge of the total phenolic content and the antioxidant activity of antioxidant ingredients allow a comparative evaluation between the preservative extracts analysed
Summary
Sheep were among the first livestock to be domesticated and used for their milk, wool, and meat.As early as the Neolithic age, from 9000 BCE, lambs were being raised in many parts of the Mediterranean and Central Asia. It is relatively easy to find high-quality lamb meat throughout the Mediterranean region, but it is mainly abundant in mountainous areas where lambs are raised in freedom. Lamb meat is considered to be a delicacy in the countries of the Mediterranean basin [1,2]. Lamb meat is a perishable product with a shelf-life of 7 to 10 days [1], because its high water activity (0.98) and pH (may reach pH 6) allow the growth of foodborne microbial pathogens [3]. For these reasons, some preservatives are used to ensure a better shelf-life. Different types of antioxidant substances are Antioxidants 2020, 9, 851; doi:10.3390/antiox9090851 www.mdpi.com/journal/antioxidants
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