Utilisation Of Pectin In Edible Coating For The Storage Of Mozzarella Cheese by Prof. Sunita Mishra, BBAU
Using pectin as an edible coating can increase the shelf life of mozzarella cheese and very few amounts of data are available subjecting to fresh cheese. Banana is an important tropical fruit all over the world. Production of bananas is around 102028.17 thousand tons globally out of which India accounts for 29.19% in which Tamil Nadu, Maharashtra, Gujarat, Karnataka are the leading states.
Although the fruit is mostly consumed fresh but can be processed into different types of products at small scale industries, that includes chips, smoothies, ice cream, dried fruits, bread, flour. It’s also used as an ingredient for functional foods.
Nowadays, banana peel being considered waste is discarded into landfills without using potential materials present in it. Banana peels are a pectin-rich material (ranging from 15.89% to 24.08%) depending on the type and variety of bananas. 40% weight of fresh banana fruit is banana peel. Pectin is found in the cell wall and middle lamellae of all plants and is a high molecular weight carbohydrate polymer. It is an amorphous and colloidal polysaccharide, which is the backbone of α (1,4) galacturonic acid. Pectin is a Greek word that comes from PEKTOS which means firm and hard. Pectin can form a gel under a certain temperature, its gelling properties mostly depend on the “Degree of methylation”.
Generally, pectin is classified into three groups- i) Pectin more than 75% of methylation, ii) Pectin less than 75% of methylation and, iii) Pectin without methyl of esterification.
In this present era of food technology, an edible coating is gaining popularity and value. The idea of edible coating is revolutionary as it helps to provide a semi-permeable barrier to gases and water vapour and it aids in controlling water loss from the products. The protective functionality of edible coating can be upgraded by the addition of few more ingredients such as antioxidants, antimicrobial, etc. There has been huge damage caused to the environment due to the use of polymer obtained from non-renewable and nonbiodegradable resources.
When we focus on available data the Municipal solid waste generated in the USA is 19.3 million tonnes. The most common method for packaging waste disposal is landfilling which is accompanied by recycling, composting, and incineration. Polysaccharides are the most suitable substances for packaging material. It complies with all environmental concerns and can be metabolized by the human body, making them perfectly suitable for use as an edible coating. Polysaccharides are substances present in abundance and have a relatively low cost for production. Pectin is one of the most significant polysaccharides with increasing demand.
Considering the data in 2011 the total demand was around 140-160 metric tons whereas production was limited to 45-50 Metric tons. This is an indication of consumer and food industries joining hands to achieve better environmental conditions. The cheese industry being evolved as a global business requires proper research focusing upon few points such as increasing shelf life of cheese, product safety, and quality. Traditionally for cheese preservation, a coating and packaging are used acting as an individual packaging material. There has been no study done on Pectin being used as an edible coating over mozzarella cheese. The shelf life of Mozzarella cheese is approximately 5 to 7 days and consistent efforts are being made in direction of increasing its shelf life.
Pre-treatment of banana peel-
The banana peel was cleaned and washed under running tap water. It was weighed 500 gm for each treatment and blended. Peels were separated based on their type and cut into slices to increase the surface area for a faster drying rate. It was then soaked in 0.5% metabisulphite solution for an hour to prevent discoloration and browning of peels, peels were placed in a hot air oven at 65˚C for 24 hours followed by cooling at room temperature. Followed by grinding of dried peels in an 80 meshes sieve size and put in an airtight glass container.
Pectin Isolation from banana
Pectin was isolated based on the best optimization result obtained by using Response Surface Methodology. 40 gm of homogenized banana peel was taken in 500 ml of a previously sterilized beaker, add 500 ml of distilled water (1:10) .To this mixture, add 21 ml of 0.5 N Hydrochloric acid (pH 2.5). Continuously stir the mixture for 2.5 hours at 90˚C with the help of a glass rod in a hot plate. The suspension is then allowed to cool down at normal room temperature and is filtered through a muslin cloth (1mm mesh size).To the filtrate, add the same amount of ethanol (absolute) and left overnight for precipitation of pectin. The next day, discard the supernatant and centrifuge at 5000 rpm for 15 min at temperature 5˚C to obtain pectin. The flocculant was then skimmed off and the resulted pectin was dehydrated using a hot air oven to achieve a constant weight. A sealed container is used to store dried pectin to prevent moisture absorption. Figure 1 shows a schematic diagram of pectin isolation from the banana peel The pectin yield can be calculated using the following expression:
𝑷𝒆𝒄𝒕𝒊𝒏 𝒚𝒊𝒆𝒍𝒅 (%) = 𝑭𝒊𝒏𝒂𝒍 𝒘𝒆𝒊𝒈𝒉𝒕 − 𝑰𝒏𝒊𝒕𝒊𝒂𝒍 𝒘𝒆𝒊𝒈𝒉𝒕 × 𝟏𝟎𝟎 ÷ 𝒔𝒂𝒎𝒑𝒍𝒆 𝒘𝒆𝒊𝒈𝒉
Edible coating of cheese-
Different methods such as spraying, brushing, dipping, and electrostatic spraying can be used in the edible coating of cheese. Here brushing was applied for pectin coating over mozzarella cheese. Very few studies have been carried out on the coating of pectin. Suspension of Coating was prepared by dissolving 3 gm of pectin .2.81 gm of starch in 50 ml of distilled water followed by 2.11 gm of glycerol (plasticizer),1.25 gm polyvinyl alcohol, and 1% of citric acid and stir for about 15 minutes on a magnetic stirrer at 90˚C, while at 80 degrees Celsius corn starch was gelatinized. After 15 minutes, the solution is allowed to degas. A transparent suspension was obtained . Thereafter, with the help of a brush, the coating was applied to cheese cubes and kept a coated cheese in the refrigerator at 4˚C for its shelf life study.
Yield and shelf life of mozzarella cheese (Coated and Uncoated)-
The yield of cheese obtained from 1 litre of milk was about 250 grams. On the first day, there was no growth of yeast and mold, coliform and uncoated cheese, on the day seventh there was a growth of 2.3×102 CFU/gm of yeast, and mold count occur over uncoated cheese. On the fourteenth day, the yeast and mold growth count over uncoated cheese was 3.5×104 CFU/gm and no growth of yeast and mold was observed on coated cheese. In all the days no growth of coliform was observed. On day 21, 2.3×102 CFU/gm of yeast and mold growth occur over coated cheese and on the 28thday, 4.5×104 CFU/gm of yeast and mold were observed in uncoated cheese. At last, it concluded that pectin coating over cheese extends its shelf life compared to uncoated.
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