Morinda citrifolia Linn Grown in Sri Lanka: Shelf life of Fruit Juice

Morinda citrifolia L has been reported to have a broad range of therapeutic effects, including antibacterial, antiviral, antifungal, antitumor, antihelmin, analgesic, hypotensive, anti-inflammatory, and immune enhancing effects. In the present study, shelf life of fruit juice of M. citrifolia grown in Sri Lanka was evaluated in terms of possibility of (a) decomposition of chemical compound/s (b) growth of microbes and (c) organoleptic properties of M. citrifolia juice at the initial stage and after 6 months. Possibility of decomposition of chemical compound/s in M. citrifolia juice was evaluated by means of (a) Thin Layer Chromatography (TLC) fingerprint profile and (b) phytochemical classes. Microbiological analysis was done by evaluating the presence or absence of microbes (eg. counts of aerobic bacteria, Staphytococcus aureus, yeast and moulds and Escherichia coli). Organoleptic properties such as color, odour and taste of M. citrifolia juice were checked. Results revealed that intensity of the spots bearing Rf values of 0.45, 0.60, 0.72, 0.80, 0.88 appeared in the TLC at the initial stage retained as similar after 6 months. Phytochemicals such as alkaloids, phenols, tannins, flavonoids, steroids, saponins were detected in both initial stage and after 6 months. Further, Escherichia coli, Coliforms and Salmonella were absent at initial stage and after 6 months respectively. Counts of Aerobic bacteria, Staphytococcus aureus, Yeast and Moulds were <1, <100 and <1 respectively in both stages. Organoleptic properties of Noni juice was similar at the initial stage and after 6 months. In conclusion, M. citrifolia fruit juice can be kept at room temperature without any chemical deterioration and microbial contamination for 6 months.


Introduction
Morinda citrifolia Linn is belonging to the family Rubiaceae. In India this plant is known as Indian Mulberry or Nuna whereas in Hawalli it is known as Noni [1]. The Noni plant is a small evergreen tree found growing in open coastal regions at sea level and in forest areas up to about 1300 feet above sea level. The plant is often found growing along lava flows. It's identifiable by its straight trunk, large, bright green and elliptical leaves, white tubular flowers, and its distinctive, ovoid, "grenade-like" yellow fruit. The fruit can grow in size up to 12 cm or more and has a lumpy surface covered by polygonal-shaped sections. The seeds, which are triangular shaped and reddish brown, have an air sac attached at one end, which makes the seeds buoyant. This could explain, in part, the wide distribution of the plant throughout the Polynesian islands. The mature Noni fruit has a foul taste and odor [2,3].
After planting M. citrifolia fruits will be appeared after 9 months to 1 year time period. The unripe fruit is dark green in color and the ripe fruit has a foul taste and odor. The pulp has a light dull yellowish white color. The ripped fruit is juicy and bitter and Noni juice is prepared from ripe Noni fruit [2,4]. It has been reported to have broad spectrum of therapeutic remedies for diseases such as diabetes, arthritis, cancer, hypertension, cough, cold,

Preparation of Morinda citrifolia juice
Fruits of M. citrifolia were washed and embedded in an amber color jar and kept for 14 days under sun light. After that, filtered and filtrate was added to 4 sterile glass bottles and sealed. These bottles were kept in the room temperature (28-30°C).

Development of a TLC fingerprint profile
Noni juice was added to a separatory funnel containing dichloromethane and mixed well. Then dichloromethane layer was separated and added to a round bottom. This was repeated for thrice and evaporated to dryness. The residue was redissolved in 2 ml of dichloromethane and spotted on a TLC plate. As the mobile phase cyclohexane, dichloromethane and ethyl acetate in a ratio of 1:4:0.5 was used and observed under 254 nm and 366 nm.

Screening of phytochemical compounds
Secondary metabolites such as alkaloids, phenols, tannins, flavonoids, steroids and saponins were screened according to methods described by Goveas and Abraham [9].

Organoleptic properties
Organoleptic properties such as colour, smell, appearance were detected in the Noni juice.

Results and Discussion
The time duration which an active ingredient/s is expected to remain within the approved specification limits under the given storage conditions is known as shelf life of a product [14]. The storage condition of a product is the most important point when evaluating the shelf life of a product [15]. In the present study, M. citrifolia juice was kept in the room temperature (28-30°C). Moreover, TLC fingerprint profile of M. citrifolia juice at the initial stage (R f values of 0.45, 0.60, 0.72, 0.80 and 0.88) was similar to the TLC fingerprint profile of the same juice after 6 months. Phytochemicals such as alkaloids, phenols, tannins, flavonoids, steroids, saponins were detected in the juice at both initial stage and after 6 months. More often, queries on microbial quality will arise for herbal beverages due to the complexity of chemical compounds rather than chemically define beverages [16].

Conclusion
In the present study, Escherichia coli, Coliforms and Salmonella were absent at initial stage and after 6 months respectively. Counts of Aerobic bacteria, Staphytococcus aureus, Yeast and Moulds were <1, <100 and <1 respectively in the both stages. Organoleptic properties of Noni juice was similar at the initial stage and after 6 months. In conclusion, fruit juice of M. citrifolia grown in Sri Lanka can be kept at room temperature without any chemical deterioration and microbial contamination for 6 months.