More than "meats" the eye

Monday, March 29th, 2021

Influencing purchases of meat & processed meat products through sight and taste. By Frauline Joseph, KEMIN.

“The eyes eat first”—this well-known adage alludes to the fact that peoples’ initial judgement of food quality is based on visual perception. Food that looks stale, unappealing or unappetising, are often less desired.

Appearance is a multi-faceted characteristic intrinsic to every food product. For instance, the cherry-red colour of red meat and pinkish hue of poultry products are coveted marks of quality. As for fish, the redness of fish gills serves as an indicator of freshness too. Scrutiny of these visual attributes is often the first stage of the consumer’s buying process.

Beyond colour as a visual cue, we also rely on a plethora of other sensory inputs to determine if a food product is of good quality. This includes smell, texture, and perhaps most prominent of all—flavour.

While the eyes might eat first, the tongue still has the last say. Visual cues are important for first impressions, but flavour tends to leave a stronger imprint on customers in influencing return purchases. Be it fresh cut meat or processed meat, product that looks good but taste bad would eventually fail the mark and be left untouched, reducing to waste when expiry draws near.

Impact of Oxidation on Meat

Oxidation is a natural and irreversible process that can be accelerated by external factors such as temperature, light and metal ions. Alas, food cannot escape the fate of oxidation. The oxygen in air will combine with nutrients in food, decreasing its nutritional quality; cause colour loss; colour change; off-odours and off-flavours.

Meat and processed meat products are particularly susceptible to oxidation due to the presence of protein and fats. When oxidized, these products would turn dull in colour and may taste rancid. Although both oxidative changes do not pose any food safety threats, it is a quality change that is undesirable, especially amongst more affluent consumers.

Figure 1: Schematic of myoglobin redox interconversions on the surface of meat

The colour of meat is associated with two proteins – myoglobin and haemoglobin, found in the muscle cells and in the blood cells respectively. When carcasses are slaughtered for meat, oxygen comes into contact with the meat, reacting with the myoglobin and causing colour change that happens in three stages. At the initial stage, myoglobin gives the meat a purplish red appearance, but this quickly turns into a cherry red colour as it oxidizes into oxymyoglobin. Further oxidation of the iron in the myoglobin, would then cause the meat to look brown, which is the last stage known as metmyoglobin. These browned meats are usually less attractive to consumers and would commonly be found at the discounted counters of supermarkets.

Fat tissues in meat becomes rancid when oxidized, producing by-products such as peroxides and hydroperoxide compounds that will impart unpleasant odours and taste. Mechanically deboned meat (MDM)—present in countries where it is allowed as a cheaper alternative protein source in processed meat products, is susceptible to rancidity through oxidation of meat lipids. As compared to whole muscle meat, the grinding process used in producing MDM significantly increases the surface area in contact with air. The mechanical grinding also breaks down the cell membrane of meat tissues and partially destroys bones, resulting in the release of iron from myoglobin and metal ions from bones. This further promotes oxidation, making MDM a class of meat that is particularly vulnerable to quality degradation.

Protection Plan For Meat

The detrimental effects of oxidation on colour and flavour of meat and processed meat products can be nullified with a protection plan in place. KEMIN holds a wide library of natural antioxidants, tailored to every need of meat and processed meat manufacturers.

Figure 2: TBARS value of frozen chipolatas stored at -18°C over 12 months

The FORTIUM R series antioxidants (rosemary extract-based ingredients), FORTIUM A (acerola extract based antioxidant, rich in source of ascorbic acid), NaturFORT series antioxidants (a combination base of rosemary and green tea extracts), are natural antioxidants designed for maximum effectiveness against colour and flavour degradation. These plant-based antioxidants allow food manufacturers to ride on the rising wave of clean labelling in the food industry.

A study to evaluate the efficacy of the natural rosemary and green tea combination NaturFORT 12 and natural rosemary extract FORTIUM R10, showed promising results in delaying lipid oxidation in frozen chipolatas (sausage typically made from ground pork).

Figure 2 displays the analysis of secondary oxidation products (TBARS) over a period of 12 months. It can be seen that both FORTIUM R10 and NaturFORT 12 were effective in delaying the formation of TBARS when compared to the untreated control chipolatas. The untreated chipolatas showed a significant increase in TBARS, especially from the fourth month onwards.

Figure 3: Sensory results of ranking preference test of frozen chipolatas over 12 months (1 = most preferred, 2 = no clear preference, 3 = least preferred)

A sensory test was also conducted based on the evaluation of odours and taste, and the graph of sensory scoring (rank preference) collated over 12 months is shown below.

The data in figure 3 shows that chipolatas treated with FORTIUM R10 and NaturFORT 12 were consistently preferred over the untreated ones. This correlates with the increase in TBARS (from the earlier graph) during the same period. Moreover, at month four and seven, the untreated chipolata was least preferred in odours and taste. This is a clear indication of the direct negative impact oxidative rancidity had on the untreated sausages, on both smell and taste.

In conclusion, both FORTIUM R10 and NaturFORT 12, are able to extend the shelf life of frozen chipolatas without affecting the sensory attributes of the product. As two of the many natural plant extracts antioxidants in KEMIN, it also qualifies for clean labelling. This can be a significant plus point, especially for processed meat products where the use of artificial additives has been controversial in recent years.

Offering More With KEMIN’s Antioxidants

Consumers today are getting affluent, and demands are growing for food that is not only safe, but also looks fresh, and taste wholesome. This pursuit for perfection means that food is cast aside and wasted for the slightest perceivable flaw, even in cases where the oxidative impact is purely aesthetical and pose no health or safety issues. KEMIN’s array of antioxidants tackles the problem by influencing purchasing decisions through protection of colour and flavour of meat and processed meat products.

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