Enhancing Quality of Palmyrah (Borrasus Flabellifer) Jaggery

Palmyrah (borrasus flabellifer) Jaggery is one of the ancient sweetening agent known to man and is an integral part of traditional diet in many parts of Sri Lanka. Jaggery is produced by concentrating the Inflorescence sap of Palmyrah palm (Sweet Toddy) to a thick consistency. The product has sweet in taste and golden yellow in colour. However existing jaggery available in the market is inferior in its quality as liquefaction and deterioration of color. It shows poor keeping qualities due to the presence of moisture. Through this research attention to be made to eradicate its hydroscopic nature in the existing jaggery to upgrade it. Optimization of quick lime (CaO) and pH of sweet toddy to produce jaggery are to be carried out. In the period of May to June different areas in Jaffna peninsula four field trials were carried out to collect sap by using quick lime with above 95% purity produced at Palmyrah Research Institute. Physical and chemical quality characteristics of produced jaggery in laboratory and commercial samples were studied according to comply with Sri Lankan standards for jaggery. Quality of jaggery was enhanced using proper technology and sweet sap with acceptable lime with higher degree of purity. For suitable jaggery production, 2.508 ± 0.411 grams of lime (96 % purity) per one liter of sweet sap was optimized and this jaggery was scored high score than jaggery from other field trials.

Key words: Palmyrah (Borrasus flabellifer) Jaggery, quick lime and sweet sap

Introduction

Jaggery industry is one of the ancient and large cottage industries in palmyrah society. The product normally made in household level has bitter taste due to the presence of excess amount of lime with low purity. As sugars are known to be hygroscopic it is possible for melting of jaggery (Molasses) due to presence of excess moisture in the environment and other moisture absorbing impurities from quick lime and triple super phosphate for deliming the quick lime and minor improper practices in processing. Even if the demand for jaggery according to their food based applications is continuously growing in the rural, urban and semi-urban markets palmyrah jaggery cannot be marketed whole of the year, means up to next season. Because sweet toddy production is seasonal and produced jaggery shows poor keeping qualities. Quick lime used in the preparation of jaggery is generally obtained from furnacing oysters (mostly sea shell in Jaffna) using coconut husk charcoal and the temperature is not up to the optimum level to produce pure lime. Therefore there is a high possible for adulteration by impurities presence in quick lime. Traditionally lime used to prevent the fermentation of sweet sap, is produced mainly from sea shell and hardly from oysters. But no studies were yet carried out on the composition and purity of quick lime used in local production. Another major issue is the local tappers are using excess amount lime which present in sweet toddy. Availability of quick lime at higher degree of purity will ensure the maintenance of extreme alkaline pH of the sweet toddy with minimum amount of it.When tappers bring limed sweet sap to the production unit at different time periods few of them get fermented and it is also used for the production. This issue leads to the poor quality of jaggery. According to these basic principles this research is proposed for improving and standardizing the quality of palm jaggery. This project will upgrade the quality of palm jaggery and increase the market demand for palmyrah jaggery.

Materials and Methods

Matured and healthy female palmyah palms were labeled near to jaggery producing areas of Jaffna peninsula in the period of May to June. From this palm, well prepared and healthy inflorescence were identified for sap collection and the sap was collected in earthen pots, which was kept under hygienic condition. Selected inflorescences were tapped in the evening between 5 to 6 p.m to ooze out sweet sap. Before attaching sap collecting pots with inflorescence according to tappers experience day before experiment day with the inflorescence underwent experiment, known amount of quick lime with 96 % purity was applied to arrest fermentation. Four field trials were carried out. Fresh sap exudation was collected at morning between 7 to 8 a.m. The pH of the sweet sap in each pot was measured by pH meter² and brix was measured by hand refractometer. Collected sweet sap in separate cans was brought to laboratory in aseptic, sterile and dark condition. Within one hour whole samples were pooled and pH of pooled sap was measured. Jaggery was produced and packed in polyethyene packets. Sensory evaluation of produced jaggery was carried out to select best samples on the basis of sensory attributes. The colour, odor, appearance, flavor and texture were evaluated by 12 untrained persons. The total acceptability of the samples was evaluated using five point hedonic scale subjectively. Collected data were statistically analyzed using the MINITAB statistical analysis package according to the Freedman nonparametric test at 5 % level of significance.

Results and Discussion

Different field visits were conduct to optimize lime for the processing of palm jaggery and all the summarized results were recorded in the table 01. In field visit 1 (T1), field visit 2 (T2), field visit 3 (T3) and field visit 4 (T4) amount of applied quick lime were 4.668 ± 0.847 g/L, 3.188 ± 0.242 g/L, 2.508 ± 0.411 g/L and 2.051 ± 0.833 g/L and pH of them were 11.51, 10.62, 9.43 and 8.23 respectively. According to Sri Lankan Standard¹ fresh jaggery samples from T1, T2 and T3 field visits at the time of packaging moisture content of all was below 10 %. Sweet sap samples with pH between 7 and 8 quickly changed into acidic medium with time and this indicates the microbial activity is present considerably. Jaggery from field visits 4 shows melting property and moisture content was below 12.5 %. It was identified that fermented sweet sap also course melting of jaggery. Therefore pH of sweet sap needs to be maintained above pH 9 in large scale application. For the suitable jaggery production without deliming step 2.508 ± 0.411 grams of lime (96 % purity) per one liter of sweet sap was optimized.

Table 01: Summary of all field visits

Sensory evaluation

Sensory data obtained through the five point hedonic evaluating test, revealed that there were significance difference in colour (p = 0.012), appearance (p = 0.003) and texture (p = 0.001) characteristic among the jaggery samples produced in the laboratory. However there were no significant difference in flaver (p = 0.296) and mouth feel (p = 0.145) among the samples. The sample code 115 gained the highest sum of the rank for the colour, appearance, and texture. Therefore code 115 sample was selected as best sample Produced jaggery in laboratory scale from all the field visits, according to the sensory evaluation quality of colour, texture and appearance were increased with decreasing pH. Produced jaggery sample from each field trials were in the figure 01.

Table 02: sensory attributes of the jaggery

Figure 01: Jaggery samples from four field visits (codes 175, 101, 115 and 142 were jaggery samples from first, second, third and fourth field visits respectively.)

Conclusion

Palmyrah jaggery would be a most popular sweetener in Srilanka. However it shows poor physico-chemical qualities. On the basis of facts jaggery can be produced without deliming step from fresh, unfermented and filtered sweet sap of palmyrah palm. Sweet sap should be maintain in pH 9 by using purified quick lime to arrest fermentation and it can be useful to get quality improved jaggery as high consumer acceptance in market.

References

1. SLS 512: 1981-Specification for jaggery – moisture content. Pp. 23
2. Mandal D, Tudu S, Mitra SR, De GC (2006). Effect of common packaging materials on keeping quality of sugarcane jaggery during monsoon season. Sugar Tech., 8(2/3): 137-142.