Reaction kinetics of physico-chemical attributes in coconut inflorescence sap during fermentation

Determining key factors affecting coconut sap quality after harvesting

The production of coconut sap beverages faces a challenge with the quality of the incoming coconut sap sourced from farmers. The clarification of pivotal factors influencing the quality of coconut sap after harvesting is of paramount importance for fostering mutual benefit between the involved parties. This research focuses on assessing the quality and degradation of coconut sap during the post-harvest stage. It addresses the shortcomings in evaluating coconut sap quality and improper pick-up conditions. To improve these processes, various experiments were designed, including 1) preliminary experiments that explored microbial count, pH, and soluble solids in harvested coconut sap at varying intervals, and 2) the L9 Taguchi Orthogonal Array method. These approaches identify the optimal levels of factors such as cleaning method, storage temperature, and preservative type. By reducing the number of experiments, costs and time were minimized, 3) the 23 factorial design was implemented, reducing the levels of each factor while measuring coconut sap quality based on pH and total soluble solids (representing sweetness) at different post-harvest intervals. The results from the Taguchi method were then used to design the factorial method experiment. The analysis revealed crucial factors influencing coconut sap quality at the 10-h mark. Storage and transportation temperatures, along with the type of preservative, significantly impacted the pH value. However, the washing method and preservative type showed no statistically significant effect on Total Soluble Solids (TSS) value (p > 0.05). Recommendations include using tap water for container cleaning, opting for Payom wood as a preservative, and adhering to cold chain practices for transportation exceeding 4 h, with temperatures maintained below or equal to 10 °C . Swift sap collection within 4 h post-harvest, coupled with stringent temperature control during transportation (not exceeding 10 °C ), is advised to ensure optimal quality. Integrating pH with TSS values enhances comprehensive quality assessment, aligning with established best practices in coconut sap handling.

Dynamics of biochemical attributes and enzymatic activities of pasteurized and bio-preserved tender coconut water during storage

The potential of bio-preservatives, namely, nisin, natamycin, and polylysine, as viable alternatives to chemical preservatives for storage of tender coconut water (TCW) during refrigerated storage (5 ± 2°C) was explored. Bio-preservative treatments were carried out after optimized heat treatment (85°C for 5 min) of TCW to establish its storage characteristics. Various concentrations (up to 125 ppm) of bio-preservatives were used for the preservation, and quality parameters of resultant TCW were assessed based on physicochemical characteristics and Food and Agriculture Organization (FAO) guidelines and statistical analysis applied. Analysis of variance (ANOVA) and post-hoc test revealed that pH and overall acceptability (OA) are the major governing factors that determine spoilage of TCW (p < 0.05). Overall, the polylysine combination was found to be most effective in ensuring quality retention of TCW. It was concluded that pasteurized TCW shelf life could be extended up to 20 days using bio-preservatives.

Low-density polyethylene based nanocomposite packaging films for the preservation of sugarcane juice

Low density polyethylene (LDPE) based nanocomposite films made from different levels of nanoclay, compatibilizer and thickness were evaluated for the storage stability of sugarcane juice for 60 days under ambient condition. During the storage period, important physico-chemical properties such as pH, total sugars, total soluble solids and overall acceptability were decreased with respect to increased level of nanoclay and compatibilizer as well as decreased thickness of film. Total plate count was nil till the storage period of 15 days and then there was an increase in microbial population. Similarly, the overall color difference was also increased during the storage period. The better storage stability with respect to biochemical characteristics, overall acceptability and microbial load was recorded in the 100 µm thick LDPE nano composite films developed from 93 percent LDPE, 2 percent nanoclay and 5 percent compatibilizer.

Impact of Nisin in Combination with Sodium Benzoate and Calcium Carbonate on the Bacterial and Yeast Population of Coconut Neera (Coconut Inflorescence sap)

A natural sap from mature coconut palm known as coconut neera is enriched with essential minerals and vitamins. Rapid microbial fermentation affects neera processing industries because it spoils the physicochemical properties. There are various methods in preservation that extend the shelf life of coconut neera. The addition of nisin is one of the methods which protect neera against fermentation. Therefore, the study is focused to identify the effective combination of nisin (50 ppm) with preservatives like sodium benzoate (500, and 1000 ppm), and calcium carbonate (2500, and 3000 ppm) at two different combinations in neera. At the end of 21 d, 3000 ppm calcium carbonate with 50 ppm nisin in N4 treatment had an effective reduction of 120 × 105 CFU/ml and 143 × 102 CFU/ml for total bacteria and total yeast count. The reduced microbial survival resulted in the pH of 10.45 ± 0.05, total soluble solids of 15.43 ± 0.12 °Brix, and total acidity of 1.11 ± 0.04 mg/ L, at this combination. The treatment of nisin with 3000 ppm calcium carbonate demonstrated the high red fluorescence bacterial cells than the treatment of nisin with 1000 ppm sodium benzoate. Additionally, the microorganisms in N4 treatment precipitated 65.34% Ca2+ from 79.96% in XRF intensity analysis. The synergistic effect of nisin and calcium carbonate explored their antimicrobial activity against the heterogeneous microbial population in coconut neera. The concentration of 3000 ppm calcium carbonate and nisin 50 ppm preserves the physicochemical and sensory qualities, up to 21 d at 4°C, and offer hope for the industrial-scale implementation.

Metagenomic Investigation Uncovers Presence of Probiotic-Type Microbiome in Kalparasa® (Fresh Unfermented Coconut Inflorescence Sap)

The phloem sap tapped from unopened inflorescence (spadix) of coconut palm using a novel collecting device, “coco-sap chiller,” has been branded Kalparasa^® (henceforth as Kalparasa in the text) to distinguish its properties not found in sap harvested by traditional methods. To know its hitherto unidentified microbiome profile, we employed high-throughput sequencing to uncover the bacteriome and mycobiome in fresh and 12-h fermented samples. Fresh Kalparasa had a pH of 7.2, which dropped to 4.5 after 12 h, signifying fermentation of the sap. Diversity analysis indicated fresh Kalparasa having higher bacterial species than the fermented one. Contrary to this, fresh sap had lower fungal/yeast diversity than the fermented sample. Fresh Kalparasa had relatively higher abundance of probiotic-type Leuconostoc genus followed by equal proportions of Gluconobacter, Acetobacter, and Fructobacillus. The 12-h fermented Kalparasa showed a significant increase in Gluconobacter with a sharp decrease in Leuconostoc. Mycobiome data revealed fresh Kalparasa to be preponderant in Saccharomyces and Hanseniaspora genera of yeasts while the fermented sap had higher representation of Hanseniaspora and Cortinarius and lesser Saccharomyces. This suggested that the fermentation of Kalparasa was probably driven by symbiotic culture of bacteria and yeasts (SCOBY), particularly acetic acid bacteria and non-Saccharomyces yeasts. The bacteriome-function predictions highlighted the enrichment of glycerophospholipid, ABC transporters, purine, and pyrimidine metabolisms. Based on our findings, Kalparasa containing large population of Leuconostoc mesenteroides, Fructobacillus fructosus, Saccharomyces cerevisiae, and Hanseniaspora guilliermondii can be promoted as a healthy “unfermented” plant edible food containing live probiotic-type microbiome during its consumption.