Visual pleasure is the pivotal concern of consumers when purchase comes in question. When the product at hand appeals to the consumer, they instantly indulge in purchasing. The color of the meat is directly proportional to the quality of the meat.
Meat manufacturers are still looking for a permanent solution to deal with preservation of the natural color of meat along with the flavor. Microbial putridness and oxidative contamination is a cause of worry for meat manufacturers. Red colored raw meat is as crucial as a well cooked meat of grey or brown color and pink colored meat that is cured. An approximate annual revenue loss of 1 billion was recorded of retail beef as the discounted sales of 15% took place once surface discoloration had occurred.
A leading capital organization conducted a survey in select retail outlets and reported that impoverished colors were the prime factors which resulted in removal of pork packages from display, making it unacceptable for consumption by consumers. Although right colored meat is considered important, a perfectly balanced piece of meat-freshness and flavor kept intact will elevate the quality of product and bring the buyer back.
MYOGLOBIN AND ITS REACTIONS
The presence of myoglobin is solely to be held accountable for the discoloration of meat. Even though existence of myoglobin gives the meat colors that make it appealing, it is also responsible for the diminished color quality. Oxidization leads to discoloration of the meat as it contains myoglobin-a protein type that facilitates oxidization. Myoglobin is structurally somewhat identical to a subunit of hemoglobin and is a red protein that contains haem. The concentration of myoglobin is higher in 1 kg of beef when compared to other lean meat like lamb, pork and poultry. The accumulation of myoglobin is of varied intensity when it comes to different animal species and is based on multiple factors like environment, sex, genes, diet and age of the organism.
Myoglobin is equally present in three forms that balance each other and internally react with oxygen and further provide the vibrant colors of red. MbO2, i.e. ox-myoglobin is responsible for providing the red color to meat which is also considered the symbol of good quality. This stable compound is formed when there is sufficient oxygen present. Till 1 cm within, there is ample oxygen present inside the layers which is why it is red overtly. As the thickness exists within, there is not enough room for oxygen to seep through the thick walls of fat thus forming myoglobin that results in low or no oxygen and gives away darker shades of purple. Consistent oxidization alters the color and transforms myoglobin into metmyoglobin which turns into brown color because of presence of iron. Unaware to this natural process of oxidization, consumers assume the decolored meat is not fresh.
Non-oxygen permeable packaging causes the meat to remain purple but the moment it comes in contact with oxygen on unpacking, it returns to red color-a mark of freshness as considered by consumers. Curing of meat is a process of preservation that is useful in extending shelf life of meat. Usage of nitrite for curing of meat results in formation of nitric oxide and combines with hemic myoglobin. Uncured fresh meat turns brown when heated while cured meat remains red even after cooking.
LIPID OXIDATION-THE CHALLENGE
Rancidness due to oxidization and microbial spoilage impacts the flavor and odor of meat products. Quality compromise of Modified Atmosphere Packaging [MAP] and frozen meat is caused by lipid oxidation. Secondary oxidative byproducts are molecules like acids, lactones, alcohols, aldehydes, alkanes, epoxides, esters, ketones and alkenes that come into existence when primary byproducts called hydroperoxides undergo lipid oxidization. In the unavailability of light, hydroperoxides further form complex mixtures of aforementioned secondary byproducts.
A phenomenon that came to be known as warmed over flavor [WOF] results in aldehydes breaking down when meat is cooked and are to be blamed for rancid flavors that taste like cardboard and paint. The membranes of meat expose lipids to oxidation when meat is cooked, minced or ground. A research concluded that it is possible for subcutaneous fat to generate roughly 50 components that are volatile when the phenomenon of WOF occurs. On the other hand, intramuscular fat can produce more than 200 volatile components.
LIGHT OXIDATION IN REFRIGERATED DISPLAYS
A photochemical reaction, known as photo-oxidation takes place between fat lipids and light when meat is placed in refrigerated displays. This process specifically takes places in meats with high fat content like bacon, ground meat and sausages. The contamination caused by light oxidation is prominent by the visible yellowness and a foul smell. Ground meat and sausages are prone to decomposition as the fats are present throughout the meat. Sausages and bacon have a shorter shelf life even after being frozen as they can last only up to three months.
When spices and herbs are mixed with processed meat and sausages, they aggravate lipid oxidation. This increase in absorption of light is caused by the presence of chlorophyll in herbs and spices. Food dyes that are based out of vegetables and are present in some processed meat also take in light and cause an increase in oxidation. Spoilage of meat revolves around the usage of chemicals and salts in meat.
Antioxidants are of absolute importance when opting for plant based food coloring as they keep the process of lipid oxidation at bay. Hydrogen atoms combine with free radicals thus resulting in delayed lipid oxidation. By forming a stable antioxidant radical, the free radical loses its power to get involved in reactions. Oxidants are responsible for keeping the meat fresh by maintaining the red color in frozen and fresh meat. There are quite a few natural plant extracts that contain antioxidants. Green tea [Camellia sinensis] and rosemary [Rosmarinus officinalis] are two of the choicest botanicals for this purpose. Catechins are water-soluble flavan-3-ols that are peculiarly related to antioxidant processes of green tea extracts. Two prominent isolated antioxidants known as carnosol and carnosic acid are connected with rosemary. Acerola cherry’s juice is a plentiful source of ascorbic acid that helps in keeping the haem iron in its compressed state. Ascorbic acid is a clean label element that potently acts as a reducing agent and facilitates delay of the process of discoloration of meat. Citric acid-a chelator by nature, implements binding of metal ions-in turn deeming it inactive and disabling any oxidative reactions. Plant based meat colors contain many such properties that make it the ideal choice for meat applications.
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