Review of Cocos nucifera L. testa-derived phytonutrients with special reference to phenolics and its potential for encapsulation.

Coconut (Cocos nucifera L.) and its value-added products are rich in medium chain triglycerides, polyphenols and flavonoids with a significant anti-oxidant potential. However, coconut and its products are underutilized for the development of nutraceuticals. Coconut testa is a brown cover of the endosperm, which is characterized with the considerable amount of phytonutrients, especially phenolics and flavonoids. The nutrient rich coconut testa is generally diverted for the production of animal feed or abandoned. Around 10-15% of the coconut kernel is removed as testa while preparing coconut desiccated powder. The coconut testa from the virgin coconut oil (VCO) industry also remains underutilized. Nevertheless, biochemical characterization of coconut testa has revealed its enormous anti-oxidant and nutraceutical potential. On the other hand there are reports describing the suitable encapsulation techniques to develop nutraceuticals from the plant-derived bioactives. In this context this review explores the prospect of utilizing the coconut testa-derived phytonutrients in developing a nutraceutical product.

Effect of coconut milk, tender coconut and coconut sugar on the physico-chemical and sensory attributes in ice cream.

The investigation was aimed to understand the effect of coconut milk, tender coconut pulp, tender coconut water and coconut sugar on the qualitative attributes of ice cream. Five ice cream formulations were laid out to substitute the major ingredients of ice cream such as, dairy milk and butter with coconut milk, skim milk powder with tender coconut pulp, refined sugar with coconut sugar and potable water with tender coconut water. Two of the formulations were exclusively non-dairy, third one was the standard dairy ice cream, fourth formulation was with the inclusion of coconut sugar in the standard ice cream and the fifth one was standard ice cream with tender coconut and coconut sugar. Proximate composition of the raw materials revealed that coconut milk, tender coconut pulp and coconut sugar can contribute to the solids-non-fat content in ice cream. Significant effect (p< 0.01) was observed on physico-chemical qualities of the mix and ice cream. Total solids, density and total soluble solids of the ice cream mixes were positively correlated. Density, one of the key physical parameters was ranged from 0.98 to 1.13 g/ cm3. Though coconut milk is acidic, the percent titratable values were within the limit. Non- dairy ice cream formulations obtained lower overrun (p < 0.001). There was a negative correlation between percent fat of ice cream and overrun. Crude fat and protein contents of the ice creams were ranged from 10.52-11.62 % and 3.42-4.94 % respectively. Inclusion of coconut products resulted in increased total phenolics and minerals (ash). Non-dairy formulations were preferred over dairy counterpart with respect to flavour and taste during the sensory evaluation carried out with four different age groups. Thus, the study enlightens the potential scope of utilization coconut products in ice cream industry. It also gave a lead towards developing non-dairy/ vegan delicacy on coconut. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-021-05279-y.

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

The study on fermentation kinetics of the coconut inflorescence sap is important to understand its shelf life at different storage conditions and to develop suitable value added products. The coconut inflorescence sap collected by using in-house developed coco-sap chiller device is called Kalparasa. The fermentation characteristics of Kalparasa were investigated at every 1-h interval under ambient (31 ± 2 °C) and refrigerated (5 ± 1 °C) storage conditions. The results reveal that pH of the sap and total sugar content decline rapidly under ambient conditions than under refrigerated conditions. Acidity, turbidity, and reducing sugar content significantly (p < 0.001) increases for the sap stored under ambient conditions. The reaction rate constant (k) of the vitamin C and total sugar degradation increases with the atmospheric fermentation. The degradation kinetics of vitamin C and total sugar in Kalparasa during natural fermentation (ambient condition) follow second-order equation whereas the reducing sugar follows the first-order equation.

Effect of elevated CO2, high temperature, and water deficit on growth, photosynthesis, and whole plant water use efficiency of cocoa (Theobroma cacao L.).

In this study, the response of 6-month-old cocoa (Theobroma cacao L.) seedlings to elevated CO2 concentration [ECO2], elevated temperature [ET], and their interaction with water deficit stress was studied in an open top chamber (OTC). Each OTC was maintained at chamber control (400 ppm CO2), [ECO2] 550 ppm, [ECO2] 700 ppm, ET 3 °C above chamber control, and ET 3 °C + [ECO2] 550 ppm. Inside each OTC, a set of plants received moisture at 100% FC, while the other set was at 50% FC, which was the water deficit stress treatment. Increasing the CO2 concentration in cocoa increased photosynthesis (Pn) by 27%, which resulted in high biomass accumulation, thus improving the whole plant water use efficiency (WUE). The impact of high temperature (Tmax), around 39 °C in ET treatment against 36 °C in chamber control, is quite severe on Pn, leaf Ψ, and biomass accumulation. Similarly, water deficit at 50% FC resulted in the leaf Ψ reducing to - 14.06 bars at which Pn, leaf area, and biomass were significantly reduced. [ECO2] could ameliorate the negative effect of high temperature and water deficit stress to certain extent. However, the relative response of cocoa seedlings to [ECO2] in improving Pn, leaf Ψ, biomass, and WUE was greater under 50% FC compared to plants at 100% FC suggested additional advantage of [ECO2] to cocoa under water limited conditions.

Predicting current and future climate suitability for arecanut (Areca catechu L.) in India using ensemble model.

Climate change has the potential to influence plant development, physiology, and distribution. Arecanut (Areca catechu L.), with its long life span of 60-70 years, thrives in a tropical habitat remains exposed to various abiotic and biotic factors. It is pertinent to comprehend the adaptation strategies of this crop towards climate change over time. The Biomod2 ensemble platform for species distribution modeling was utilized to predict the potential impact of climate change on the adaptability of the crop. The extracted study region of India was used for prediction, and the final run of 6 models ensemble includes 894 occurrence points and 9 climate variables with 80%-20% of training and validation sets. The model's outputs had area under curve (AUC) values of 0.943 and true skills statistics (TSS) of 0.741, which are regarded as accurate. The research area was categorized into five groups: very high, high, moderate, low, and very low. The examination involved assessing the shift in each category from the present to two prospective scenarios (shared socio-economic pathways; SSP 2-4.5 and SSP 5-8.5) projected for the 2050s and 2070s. A shift in the climate suitability area from 'very high' and 'high' categories to 'moderate' or 'very low' categories was observed suggesting the need for adaptive strategies to sustain the current yield levels. Amongst the regions, Karnataka state, which at present has more than 50% area under cultivation, is highly vulnerable and more area is coming under 'very low' and 'low' categories from eastern side. Meanwhile, in north eastern part of the country a shift in high suitable region from northwest to southwest is observed. Overall, the model prediction suggests that some parts of west and south interior regions of the country warrant immediate consideration in order to adapt to future climate change, whereas some part of north east can be considered for future cultivation.

Evaluation of unmanned aerial vehicle for effective spraying application in coconut plantations.

Unmanned aerial vehicle (UAV) pesticide application in recent years owing to its importance such as time saving, reduction in human drudgery and also reduction in pesticides application rate. UAV has a great potential to address the problem involved in manual chemicals spraying in tall crops like coconut plantation where at present operation performed by manual climbing involves lots of drudgery and life risk. The current study aimed to understand the most influencing spraying parameters, such as spray height and spray time of the UAV sprayer on droplet characteristics such as spray droplet size, spray coverage and spray deposition at different layers (spindle, middle and bottom) of coconut tree canopy. The selected spray height (1, 2 and 3 m) and spray time (5, 8 and 11 s) significantly affects (p < 0.05) the droplet size (µm), spray coverage (%) and spray deposition (µl cm-2). In spray droplet size, the treatment T4, T5, T7 and T8 were recorded recommended droplet size of 50-400 µm in all layer of the coconut tree canopy. In spray coverage, the nearest value for recommended spray coverage of 10-20 % was observed for T1 and T5 treatment in all layer of the coconut tree canopy. The maximum penetration efficiency of 34.41 % had achieved at spray height of 2m and spray time of 8s (treatment T5). Based on performance of selected parameter, the spray height of 2 m and spray time of 8 s (treatment T5) was found best for spraying operation using UAV in coconut tree. The results showed the performance of the UAV offers best alternative for spraying operation on coconut tree and also this system will drastically reduce application time, labour requirement and improved the safety of coconut farmers.

Physical, Chemical and Functional Attributes of Neera Honey Infused Extrudates.

Owing to the demand for the consumption of healthy extrudates, this study explored the infusion of neera (coconut inflorescence sap) honey in rice flour, corn flour and coconut milk residue blend-based extrudates. Neera honey, the concentrated coconut inflorescence sap, has numerous nutrients and a natural source of essential vitamins. Hence, the potential of neera honey as a biofortifying compound for the production of healthy extrudates was investigated. The rice and corn based extrudates supplemented with different concentration of neera honey have been prepared until the mix reaches 16 and 20% (w.b.) of feed moisture. Effect of addition of neera honey on the physical properties (expansion ratio, bulk density, specific length), functional properties (water absorption, water solubility, oil absorption), biochemical properties (total carbohydrates, total sugar, reducing sugar, phenolics, flavonoids, antioxidants), color parameters(L*, a*, b*), proximate compositions (moisture content, ash, protein, fat) and mineral profile of extrudates were recorded. Results suggest that addition of neera honey had a significant (p ˂ 0.05) impact on all the physico-chemical parameters evaluated. Incorporation of neera honey (feed moisture -20%) resulted in extrudates with less expansion, high bulk density and specific length, having high sugar, protein, phenolics, vitamin C and antioxidant activity. The combination of 60% rice flour + 25% corn flour +15% coconut milk residue samples infused with neera honey upto 16% feed moisture was found suitable for the preparation of nutritious extrudates based on functional characterization and minerals evaluation.

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.

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.

Understanding Physiology and Impacts of High Temperature Stress on the Progamic Phase of Coconut (Cocos nucifera L.).

The reproductive phase of coconut is extremely sensitive to high temperature, manifesting as button (female flower) shedding and poor nut set. The progamic phase, which elapses from pollination to fertilization, is one of the most critical phases during the sexual reproduction processes in annuals and fruit trees and is extremely vulnerable to high temperature. Hence, we investigated the progamic phase of the tall coconut cultivar West Coast Tall (WCT) and the effect of high temperature on the phase under both in vivo and in vitro conditions. Coconut has a long pistil and its length was found to be 18.2 ± 4.9 mm in WCT. Pollen germination on stigma occurred one day after pollination and the pollen tube traversed through the pistil and reached micropyle of ovule four days after pollination at 29 °C. However, high temperature (Tmax > 33 °C), both under in vivo and in vitro conditions, significantly reduced pollen tube growth through the pistil, suggesting its inability to reach the ovule on time to effect fertilization. High temperature also advanced nectar secretion and stigma receptivity and the receptive stigma was dry without nectar, rendering it unappealing to insect pollinators. Thus, both poor pollination and the inability of pollen tube to reach the ovule on time to effect fertilization could be the cause of poor nut set in the coconut variety WCT under high temperature. However, it was encouraging to note that the pollen tube growth was less vulnerable to elevated temperature under high humidity, suggesting that climate change effect on coconut in coastal regions with high humidity might be less severe.

Biochemical and nutritional characterization of coconut (Cocos nucifera L.) haustorium.

Study was conducted to determine the biochemical constituents in coconut (Cocos nucifera L.) haustorium, a spongy tissue formed during coconut germination. Results indicated that 100g of dried coconut haustorium contained 1.05±0.2% ash, 44.2±4.6% soluble sugar, 24.5±3.2% starch, 5.50±0.3% protein, 1.99±0.9% fat, 5.72±0.4% soluble dietary fibre, 20.3±1.9% insoluble dietary fibre, and 146±14.3mg phenolics. Mineral profiling showed that it contained 145±8.6, 104±9.6, 33.9±8.2, 30.9±1.9, 9.45±2.1, 0.292±0.1, 2.53±0.2 and 1.20±0.1mg of K, Mg, Ca, P, Mn, Cu, Fe and Zn, respectively. Antioxidant activity assay indicated that 100g haustorium was equivalent to 1918±173, 170±20.4, 72.8±14.7 and 860±116mg of Trolox as measured by CUPRAC, FRAP, DPPH and ABTS, respectively. Amino acid score indicated that methionine+cysteine (57.6%), phenylalanine+tyrosine (32.6%), leucine (45.7%) and isoleucine (68%) are found less in haustorium. Further studies needed in developing nutritionally balanced formulations using coconut haustorium, which will be useful for lactose intolerant children.

Effect of external electrical field on mobile water fraction and physiological processes in wheat (Triticum aestivum) leaves.

Experiments were conducted to study the effect of external electric field on physiological processes, moisture content and mobile water fraction in wheat leaves. Application of electric field increased the stomatal resistance immediately and it continued to increase upto 10 min. Photosynthesis and respiration of leaves decreased with the application of external electric field. Leaf moisture content and mobile fraction of water measured as relaxation times were marginally increased with electric field. Closure of stomata, in spite of maintaining higher leaf moisture content of the leaf with external electric field, suggested that electric field might have regulated stomatal movement through hormones or ion flux across the cells.