Characterization of Palmyra palm (Borassus flabellifer Linn.) sap after harvest across different pH ranges for production of palm sugar

The quality of palm sap harvested from the inflorescence of Palmyra palm (Borassus flabellifer Linn.) trees can vary significantly from one container to another, affecting the production of palm sugar. Assessing the pH of the sap is a quick and convenient method for farmers to gauge its quality in Palmyra palm fields. In this study, palm sap collected from various containers was categorized into four groups based on different pH ranges. The objectives were to assess the physical, chemical, and microbiological characteristics of each group and to correlate these characteristics using principal component analysis, as well as to produce palm sugar from each group. The findings revealed that the palm sap with a pH below 5.0 (pHA) exhibited higher levels of reducing sugars, titratable acidity, and total phenolic substances, along with increased lactic acid bacteria (LAB) loads, larger particle sizes, lower contents of total and non-reducing sugar, protein, amino acids, and browning color values compared to sap from other pH ranges (pHB: 5.6–6.5, pHC: 6.9–7.5, and pHD: above 8.0). Principal component analysis indicated similarities between the palm sap groups of pHC and pHD, which were highly correlated with protein and total amino acids, total sugar contents, browning index, and color values of a* and b*. Conversely, pHA was distinct, being highly correlated with reducing sugar and total phenolic contents, titratable acidity, LAB loads, L* value, and particle volume. Meanwhile, pHB showed a high correlation with potassium and calcium contents, % transmission, electrical conductivity, and coliform loads. Crystallization of palm sugar derived from pHA sap was challenging, whereas sugar from the other sap groups readily crystallized. It can be concluded that pH evaluation strongly contributed to parameters of palm sap quality for palm sugar production.