Effect of storage time on the microbial, physicochemical and sensory characteristics of ovine whey-based fruit beverages

The aim of this study was to establish the physicochemical, sensory and microbiological quality of ovine whey-based fruit beverages produced from pasteurised ovine whey (mango flavoured–sugar sweetened [M-Su], pineapple flavoured–extra sugar sweetened [P-ESu], and tropical fruit flavoured–stevia sweetened [T-St]), and the changes in quality of these beverage types during the 15-day storage. The beverages were evaluated for their pH, colour, sediment and particle size distribution, microbiological count and sensory quality. No significant differences in the pH and the microbial counts among the beverages were noted during the storage period; however, the particle size distribution reflected the sediment formation that significantly decreased during the same period in all beverage types. The beverages were getting lighter during storage, which was evident by increasing L* and decreasing a* values for colour. All three beverage types had very high scores for taste and odour after 9 days, and colour and sediment after 5 days of storage. Beverage-type T-St was most preferred by consumers, with the highest scores for taste, odour and sensory appearance. These results can assist in the better determination of the deteriorative changes in a variety of ovine whey-based beverages, necessary changes in product composition that might result in improved product quality, and yet reducing losses incurred during ovine milk processing. In this sense, this research's findings contribute to the utilisation of whey beverages by the dairy industry to the development of functional products

Meat tenderness: advances in biology, biochemistry, molecular mechanisms and new technologies

Meat tenderness is an important quality trait critical to consumer acceptance, and determines satisfaction, repeat purchase and willingness-to-pay premium prices. Recent advances in tenderness research from a variety of perspectives are presented. Our understanding of molecular factors influencing tenderization are discussed in relation to glycolysis, calcium release, protease activation, apoptosis and heat shock proteins, the use of proteomic analysis for monitoring changes, proteomic biomarkers and oxidative/nitrosative stress. Each of these structural, metabolic and molecular determinants of meat tenderness are then discussed in greater detail in relation to animal variation, postmortem influences, and changes during cooking, with a focus on recent advances. Innovations in postmortem technologies and enzymes for meat tenderization are discussed including their potential commercial application. Continued success of the meat industry relies on ongoing advances in our understanding, and in industry innovation. The recent advances in fundamental and applied research on meat tenderness in relation to the various sectors of the supply chain will enable such innovation

Structural determinants of the quality of cooked meat

© 2020 Rozita Spirovska VaskoskaThe quality of cooked meat is valuable for consumers and meat industry. The aim of this research was to identify structural determinants of the quality of cooked meat. Muscle type (bovine semitendinosus, psoas major, biceps femoris), cooking temperature (45 C to 85 C), ageing time (14 vs 0 days in beef; prolonged 15 vs conventional 3 days in pork), enzyme inhibition (with/without cathepsin inhibitor) and fibre type (bovine masseter 100 percent type I; cutaneous trunci 93 percent type II) were investigated factors affecting meat quality. Methods for measuring quality (cooking loss and Warner- Bratzler shear force (WBSF)), structural changes (shrinkage) and protein denaturation [Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared (FTIR) microspectroscopy] were used. Cooking loss was higher in semitendinosus compared to biceps femoris and psoas major; and it increased with temperature in beef and pork. Cooking loss increased with ageing of beef independent of temperature and muscle type; and decreased with prolonged ageing compared to conventional ageing, of pork (cooked at 70 C and 80 C). The denaturation enthalpy of masseter and cutaneous trunci explained 58 and 59 percent of the variation in cooking loss, respectively. Reduction of WBSF in bovine muscles rich in collagen (all but psoas major) with cooking at 60 C to 65 C was attributed to collagen denaturation. The increase in WBSF in unaged beef with cooking at 70 C and 80 C was attributed to intact titin denaturation. In relation to shrinkage, 3D laser scanning was compared to caliper measurements, and was found inferior in measuring volume and predicting cooking loss. Cuboids` transverse and longitudinal shrinkage were higher in muscles with higher collagen content and sarcomere length, respectively. Transverse shrinkage started 5 C higher in psoas major fibre fragments, compared to semitendinosus and biceps femoris, likely due to predominant type I fibres. It was proven that transverse and longitudinal shrinkage of fibre fragments is caused by myosin and actin/titin denaturation, respectively. Since ageing reduced the longitudinal shrinkage of cooked beef (biceps femoris and psoas major cuboids at 80 C, semitendinosus and biceps femoris fibre fragments at temperatures greater or equal to 75 C) and pork, an important role of titin in longitudinal shrinkage was hypothesized. Cathepsin inhibition reduced the longitudinal shrinkage (semitendinosus, biceps femoris, psoas major cooked at temperatures greater than 75 C), and increased the transverse shrinkage (semitendinosus at temperatures greater or equal to 60 C) of fibre fragments. Longitudinal and transverse shrinkage were major contributors to cooking loss (beef and pork) and WBSF (beef), respectively. Cutaneous trunci had higher cooking loss (at temperatures lower or equal to 75 C), higher transverse (at temperatures lower or equal to 60 C), longitudinal (at temperatures lower or equal to 80 C) and volume shrinkage of fibre fragments (at temperatures lower or equal to 65 C); as well as lower transition temperature of myosin, higher reduction in alpha-helix and beta-sheet, and higher, compared to masseter, formation of beta-aggregated strands, random coil and aromatic side chains (at temperatures lower or equal to 60 C). The differences in protein denaturation and shrinkage between masseter and cutaneous trunci cooked at 55 C were attributed to the myosin isoform, while the differences in muscle fibre and connective tissue proteins’ denaturation at 60 C and 65 C were pH dependent. Myosin (isoform, denaturation), actin (denaturation), titin (degradation, denaturation), collagen (content, denaturation) and sarcomere length were proven or postulated, as structural determinants of the quality of cooked meat

Transparency and consumer trust in scientific assessments under European food law

European food law is a newly developing field in which different branches of law come together. The field is however also unmistakably linked with nutritional sciences, in requesting scientific evidence to ensure safety and benefits of foodstuffs. The risk analysis cycle introduced in Regulation (EC) No 178/2002, ensures that scientific information – regarding i.a. the safety of a product – is independently and transparently assessed by risk assessors who are not involved in the final political risk management decision, in which this scientific information is used to allow such a product on the market. The European Food Safety Authority’s mission as assessor is to independently and transparently conduct risk assessments, which are published in scientific opinions. Transparency of both the procedure and of the Authority’s role, key in these assessments, are however two of the shortcomings identified in the evaluation of the Regulation 178/2002 that was conducted recently. In a proposed update of the Regulation, transparency of risk assessment is therefore one of the main aspects to be improved. This originates from the understanding that such improved transparency of the European food safety system will result in increased consumer trust. After shorty reviewing the development of European food law and the proposed adjustments to the framework regulation, this chapter shows that the concept of transparency, mostly understood as increasing the availability of information, requires to be further specified to ensure it actually contributes to consumer trust. The proposed adjustments to the Regulation 178/2002 are expected to increase information availability, whilst improved risk communication strategies might aid in establishing consumer trust. Further specifying the concept of transparency will result in an increased understanding of how to operationalise it and how transparency can contribute to increasing consumer trust