Stability Studies on Ascorbic Acid content in various fruits, Vegetables and their Cocktail Juices
S. Chaitanya kumari
1and Dr. P. Naga Padma
1*1Bhavan’s Vivekananda College of sciences, Humanities and Commerce, Sainikpuri, Secunderabad-94, Telangana State, India.
1*Corresponding Author : [email protected]
ABSTRACT
Naturally occurring vitamin C predominantly is ascorbic acid and is found in many fruits and vegetables. It is a naturally occurring complex organic compound with antioxidant properties that cannot be synthesized and needs to be taken in diet to meet the daily requirement. Synthetic ascorbic acid is different from natural one and it effects the bacterial growth not differentiating between beneficial gut flora and pathogens, thus making it mandatory to depend on natural ascorbic acid found in different fr uits and vegetables. The present study was done to estimate ascorbic acid in fresh fruits and vegetables, their cocktails. Stability studies were done to determine quantitative variation of ascorbic acid in cocktails for a period of one month with and without tartaric acid addition. Tartaric acid acts both as an acidulant and a natural preservative that prevents microbial growth or spoilage.
Ascorbic acid estimation was done in different fruits like banana, grape, papaya, apple, green apple, pine apple, orange, pomegranate and vegetables like carrot, beetroot, goose berry, tamarind , lemon, tomato, garcinia. Based on the ascorbic acid content of fruit juices and vegetable juices different cocktails were prepared and tested for their ascorbic acid content. The combinations studied were cocktails of lemon, orange, apple; lemon, banana, guava; banana, lemon, pomegranate; carrot, apple, lemon; apple, orange, lemon and bottle gourd, goose berry, carrot. The ascorbic acid was estimated by viscometric method using DCPIP. Among the fruits estimated ascorbic acid content was highest in strawberry followed by lemon, orange and papaya. Among vegetables highest was in cabbage, followed by goose berry (amla) and bottle gourd. In case of cocktails of fruit juices the highest was lemon, orange, apple and for vegetable mixture it was bottle gourd, goose berry, carrot. This study is significant as different cocktails of fruit and vegetable juices can be recommended for the dietary requirement of ascorbic acid.
These selected sources had tartaric acid which is an acidulant that prevented microbial spoilage and also added to stability of vitamin C in the cocktails. The significantly highest content of ascorbic acid was observed at the start of experiment, it decreased in different percentages in the cocktails every ten days and there was slight decrease in ascorbic acid content even after one month indicating its good stability.
Keywords – Ascorbic acid, tartaric acid, cocktails, storage.
1. INTRODUCTION
Vegetables and fruits are major constituents of human diet.
Vegetables serve as source of minerals, vitamins, certain harmone precursors as well as proteins and energy [1].The consumption of fruits and vegetables in diet protects the body from degenerative diseases [2]. Fruit juices are a significant
source of ascorbic acid for humans and their consumption in the last years increased at very quick rates. However, ascorbic acid of fruit juices is readily oxidized and lost during storage of the juices, at rates depending on the conditions of storage and time. It is evident therefore that the quality of any fruit juice and its value as a source of vitamin C depends on its content and its rate of loss upon storage. Some fruits and
vegetables have both ascorbic acid and tartaric acid. Presence of tartaric acid increases shelf life of juices and adds to stability of ascorbic acid in the juices. There are many studies for determining the ascorbic acid content in fruit juices [3] but only a few aim at determining the amounts of ascorbic acid lost from different fruit juices under different storage conditions [4]. This fact is of great importance to the consumer who must know how to store the juice in containers and when to consume them in order to get the maximum benefits of their vitamin C content.
Ascorbic acid (trivial name-Vitamin C) is an essential constituent in ones daily life. Biomolecules of plant origin play a crucial role in promotion and maintenance of health [5].
In Asian countries like India, China, Japan and Korea foods and plant materials are used for their healing properties. These materials in addition, occupy an important place in traditional medicine for curing different ailments [6]. Antioxidants that are prepared commercially contain Ascorbyl palmitate, L- ascorbic acid and its fatty acid esters which are widely used as food additives, antioxidants, oxidation (browning) inhibitors, reducing agents, flavour stabilizers, dough modifiers and colour stabilizers. Ascorbic acid deficiency leads to scurvy.
Characteristic features of scurvy includes, spongy swollen bleeding gums, dry skin, open sores on the skin, fatigue, impaired wound healing and depression [7, 8, 9].
Ascorbic acid, an important water soluble vitamin is essential for collagen, carnitine and neurotransmitters biosynthesis.
Ascorbic acid serves as an important cofactor for enzymes (hydroxylases and monooxygenase). Ascorbic acid is equally important in immune functions [10] and improves the absorption of non-heme iron[11], this is the form of iron present in plant-based foods.
In the present study, ascorbic acid and tartaric acid content was evaluated in some selected fruits and vegetables and their cocktails by titration method. The stability of ascorbic acid in these for a period of 30 days was studied.
2. MATERIALS AND METHODS
Fruits like Banana, grapes, papaya, apple, pine apple, strawberry, orange, pomegranate and vegetables like carrot, bottle gourd, lemon, ginger, tamarind, garcinia, goose berry,
cabbage, tomato were purchased from local market in Hyderabad city. The fruit and vegetables cocktails were prepared in 1:1 volume .
2.1 Sample extraction
Before the extraction procedure, all the samples were thoroughly cleaned with deionized water to remove any adhering contaminants if present. 5g of sample was accurately weighed and ground in a mortar and pestle or electric grinder with the addition of 10 ml of 4% oxalic acid. The mixture was further ground and strained through four layers of muslin cloth. The final volume of the extract was made up to 25 ml with 4% oxalic acid in a standard flask [12]. All the samples were similarly treated.
2.2 Ascorbic acid assay
Ascorbic acid content in fruits, vegetables and their cocktails was determined by 2, 6-dichlorophenol indo phenol (DCPIP) titration method [13,14]. 5 ml of working standard (500µg/5 ml) of ascorbic acid and 10 ml of 4% oxalic acid were pipetted out into a 100 ml conical flask. The contents in the flask were titrated against the dye solution (V1) until the appearance of a pale pink colour that persisted for a few min.
5 ml of the test sample was similarly titrated against the dye solution (V2). Ascorbic acid content present in the test samples were determined using the formula:
Amount of ascorbic content (mg/100g) = 500 x V2 x 25 x 100 --- V1 x 5 x 5
Where; 500 = µg of standard ascorbic acid taken for titration V1 = Volume of dye consumed by 500µg of standard ascorbic acid
V2 = Volume of dye consumed by 5 ml of test sample 25= Corresponds to total volume of the extract 100 = Ascorbic acid content/100g of the sample 5 = Weight of sample taken for extraction 5 = Volume of the test sample taken for titration.
2.3 Tartaric acid assay
A fixed volume of fruit or vegetable sample as juice is taken and 3 drops of phenolphthalein indicator is added. This is titrated against 0.1M solution of NaOH taken in burette.
While titrating, care is taken to frequently swirl the solution in the beaker to keep it thoroughly mixed and also slow addition is preferred. It is important to determine the point of neutrality or the end point of titration very exactly. The phenolphthalein indicator changes very rapidly from colourless to pink at the end point[15]. The exact end point is noted with care and accuracy. The burette reading is recorded and amount of tartaric acid calculated using the formula:
1 ml of 0.1 mol/l sodium hydroxide = 7.504 mg of C4H6O6
3. RESULTS AND DISCUSSION
The present study concentrated on evaluation of ascorbic acid and tartaric acid content in fruits and vegetables and their cocktails by titration method. The stability of ascorbic acid in these for a period of 30 days was also studied to ascertain the shelf life of these juices and retention of their nutritive value. The studies indicated that different fruits had different content of ascorbic acid in their juice concentrates ( Figure 1). The highest ascorbic acid content was in strawberry-46mg/100g, this was followed by orange- 42mg/100g, papaya -35.6mg/100g etc. Among the vegetables highest content was observed in lemon- 46mg/100g followed by cabbage-32mg/100g, amla- 24.3mg/100g and so on (Figure 2). The highest ascorbic acid content in cocktails after 10 days of storage was in lemon, orange, apple cocktail -142 mg/100g, followed by bottle gourd, amla, carrot cocktail -102 mg/100g, broccoli, banana, straw berry cocktail - 97mg/100g etc. Similarly the highest ascorbic acid content in these same cocktails after 30 days of storage was in nearly same showing very little variation as indicated in figure 4. The selected fruits and vegetables under study also had tartaric acid that added both to taste and stability. The significantly highest content of tartaric acid was observed in garcinia, tamarind, and grapes with values of 2, 1.5, 0.8 mg/ 100g respectively (Figure 5).
Tartaric acid acts as both an acidulant and a natural preservative that enhances the stability of vitamin C in the source materials.
Figure 1.Ascorbic acid content in fresh fruit juices.
Figure 2. Ascorbic acid content in fresh vegetable purees or juices
Figure 3. Ascorbic acid content of different fruit and vegetable cocktails after 10 days
Figure 4. Ascorbic acid content of different fruit and vegetable cocktails after 30 days
Figure 5. Tartaric acid content in different fruits and vegetables.
4. CONCLUSION
The study on determination of content of ascorbic acid in fruits and vegetables was significant as it gave idea about the selection of source in isolation and also their combination in cocktail with highest amount of ascorbic acid. These selected sources also had tartaric acid an acidulant that prevented microbial spoilage and also added to stability of vitamin C in the cocktails. This study is significant as different cocktails of fruit and vegetable juices can be recommended for the dietary requirement of ascorbic acid which is important to boost the immunity.
5. ACKNOWLEDGMENT
The authors (Chaitanya and Naga Padma) are grateful to the management of BVB Bhavan’s Vivekananda College for their encouragement to carry out this work.
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