Description:FIELD OF INVENTION
The present invention relates to the field of food processing and preservation, particularly to the development of coconut water concentrate. More specifically, it concerns a novel method for preparing high-quality coconut water concentrate using rotary vacuum evaporation under controlled low-temperature and reduced-pressure conditions. The invention lies within the domains of food technology, nutraceuticals, and functional beverage formulation, addressing the challenges of preserving heat-sensitive nutrients, phytochemicals, and sensory qualities of coconut water while extending its shelf life and improving storage and transportation efficiency.
BACKGROUND OF INVENTION
Coconut water is a natural, nutrient-rich beverage containing essential electrolytes, sugars, phenolic compounds, and antioxidants. It is widely consumed for its hydrating and functional properties. However, coconut water is highly perishable due to microbial susceptibility and enzymatic degradation. Its sensitivity to heat presents significant challenges during processing and preservation. Conventional methods such as thermal evaporation, spray drying, and freeze-drying have been explored, but each suffers from limitations.
Thermal evaporation and pasteurization at high temperatures often result in the loss of heat-sensitive nutrients, including vitamin C and antioxidant compounds, while adversely affecting the natural flavor, color, and aroma of coconut water. Spray drying, though effective for producing powders, involves high thermal load and the addition of carriers, which compromise the clean-label nature of the product. Freeze drying offers better nutrient retention but is economically unfeasible for large-scale applications.
To minimize the loss of nutrients and sensory quality during coconut water processing, this invention introduces a method using rotary vacuum evaporation. Coconut water is highly perishable and sensitive to heat, leading to degradation of vitamin C, antioxidants, and flavor during traditional processing. Rotary vacuum evaporation operates under reduced temperature and pressure, allowing concentration without significant thermal damage. This technique ensures better retention of nutritional and phytochemical compounds, improved flavor, extended shelf life, and eliminates the need for chemical preservatives—making it a superior method for producing high-quality coconut water concentrate.
WO2014073991A disclosed a method for the preparation, extraction, preservation and utilization of tender coconut water and the often-discarded matured coconut water. The present invention aims to provide a method for the preservation of coconut water while retaining its nutrients. This, however, may not be construed as to limit the use of the same disclosed method for application on known fruit extracts.
US20180092382A1 disclosed a shelf stable coconut water concentrate is described along with a method of producing a ready to drink fountain coconut water beverage from the coconut water concentrate. The resulting ready to consume fountain drink is made solely from freshly sourced or processed coconut water without adding other fruit juice, additives, enzymes, flavorings, colorings or preservatives. A coconut water stock is concentrated by an evaporation process to obtain a coconut water concentrate of at least 70°Brix having a water activity of 0.7% or below. The coconut water concentrate is microbiologically stable at room temperature without the addition of additives or preservatives, and does not require refrigeration. Water or other liquids are added to the coconut water concentrate at a ratio of between 20 to 30 parts water to 1part stable coconut water concentrate, to form a variety of coconut water fountain drinks.
HK40011717A disclosed a shelf stable coconut water concentrate (hereinafter "CW") and more particularly to a coconut water concentrate that is free of additional other fruit juices or additional non-concentrated coconut water, additives, enzymes, flavorings, colorings or preservatives. Also provided is a process for obtaining a coconut water concentrate that is microbiologically stable at room temperature without the addition of additives or preservatives. Further, the present invention provides a coconut water concentrate having a water activity of 0.7 or less of at least 70 ° Brix for use in a fountain beverage machine, the coconut water concentrate being reconstituted into single strength (single strength) coconut water for drinking.
US20180092382A1 disclosed a shelf stable coconut water concentrate is described along with a method of producing a ready to drink fountain coconut water beverage from the coconut water concentrate. The resulting ready to consume fountain drink is made solely from freshly sourced or processed coconut water without adding other fruit juice, additives, enzymes, flavourings, colourings or preservatives. A coconut water stock is concentrated by an evaporation process to obtain a coconut water concentrate of at least 70°Brix having a water activity of 0.7% or below. The coconut water concentrate is microbiologically stable at room temperature without the addition of additives or preservatives, and does not require refrigeration. Water or other liquids are added to the coconut water concentrate at a ratio of between 20 to 30 parts water to 1 part stable coconut water concentrate, to form a variety of coconut water fountain drinks.
Research gap
Although coconut water is widely recognized for its nutritional and functional value, its commercial processing and preservation remain challenging due to its high perishability, microbial susceptibility, and sensitivity of bioactive compounds to heat. Conventional concentration methods such as thermal evaporation, spray drying, and freeze-drying are either nutrient-destructive (loss of vitamin C, phenolics, and antioxidants) or economically unfeasible for large-scale applications. Existing literature shows limited success in retaining the natural sensory qualities (flavor, aroma, and clarity) of coconut water while simultaneously maintaining its physicochemical and phytochemical integrity.
Currently, no standardized low-temperature, energy-efficient, and scalable process is available that can concentrate coconut water while minimizing degradation of heat-sensitive compounds and extending shelf life. Moreover, systematic studies combining pasteurization with controlled rotary vacuum evaporation parameters (temperature, pressure, endpoint Brix) and supporting data on nutritional, antioxidant, and phenolic retention are lacking.
This gap highlights the need for a specialized process that preserves the natural properties of coconut water while ensuring product stability, consumer acceptability, and commercial viability.
None of the prior art disclosed what the present invention disclosed. Present invention relates to a Process for Preparation of Coconut Water Concentrate by Rotary Vacuum Evaporation with Enhanced Retention of Nutritional and Sensory Properties.
SUMMARY OF INVENTION
This invention presents a novel process for producing coconut water concentrate using rotary vacuum evaporation to retain nutritional, sensory, and phytochemical properties while extending shelf life. Coconut water is highly nutritious but perishable and sensitive to heat; conventional thermal methods often degrade vital compounds such as vitamin C and antioxidants. To overcome this, the method employs rotary vacuum evaporation at low temperature (45–50°C) and reduced pressure (200–250 mbar), minimizing thermal damage and preserving quality.
The process involves: selection of fresh coconuts, hygienic extraction, filtration, pasteurization (70–75°C for 20–30 minutes), evaporation to 20–25°Brix, and final packing/storage. The concentrate retains natural color, aroma, and taste while being more stable and easier to transport.
Experimental results confirmed improved stability and nutrition: pH (4.609) and acidity (0.1217%) ensured microbial safety, reducing sugars and carbohydrates were well preserved, vitamin C degradation was minimized, antioxidant activity remained high (94.71% DPPH inhibition), and phenolic compounds were effectively retained (absorbance 0.31–0.47).
The resulting concentrate is suitable for functional beverages, smoothies, sports drinks, nutraceuticals, and natural sweeteners. Overall, the invention offers a clean-label, minimally processed solution that enhances shelf life, nutritional value, and consumer appeal of coconut water.
BRIEF DESCRIPTION OF DRAWINGS
Fig1. Coconut Water Concentrate by Rotary Vacuum Evaporation Method
Fig 2. Preparation Steps of coconut water concentration:
DETAILED DESCRIPTION OF INVENTION
This invention focuses on the development of coconut water concentrate using a rotary vacuum evaporation method to enhance its sensory, physicochemical, and phytochemical properties. Coconut water is a naturally hydrating, nutrient-rich beverage containing essential electrolytes, natural sugars, phenolic compounds, and antioxidants. However, its high perishability and sensitivity to heat make processing and preservation a major challenge. Conventional thermal processes often degrade key nutrients such as vitamin C and antioxidants. To overcome this, the present invention applies rotary vacuum evaporation—a gentle and effective concentration technique that preserves nutritional integrity.
The process begins with the selection of fresh green coconuts, ensuring they are clean, undamaged, and microbiologically safe. Coconut water is extracted hygienically, and the inner pulp may be included to enhance the nutritional value. The extracted liquid is then passed through filtration using a fine mesh or muslin cloth to remove fibers and suspended solids.
The filtered coconut water undergoes pasteurization at 70–75°C for 20–30 minutes. This thermal pre-treatment deactivates spoilage microorganisms and enzymes, ensuring product safety and stability without causing significant thermal degradation of heat-sensitive nutrients.
The pasteurized coconut water is then concentrated using rotary vacuum evaporation at a temperature of approximately 45–50°C under a vacuum pressure of 200–250 mbar (millibar). This environment lowers the boiling point of water, allowing efficient evaporation without exposing the product to damaging high temperatures. The low thermal load is critical for preserving bioactive compounds such as vitamin C, phenolics, and antioxidants, which are highly susceptible to heat degradation. The method also helps retain natural color, aroma, and flavor, producing a high-quality concentrate with minimal changes from the original liquid.
The endpoint of the evaporation process is determined by measuring Brix, with a target concentration between 20–25°Brix, depending on the intended application. This concentration increases shelf life and reduces product volume, improving transportation and storage efficiency.
Process Steps
1. Selection of Raw Material
Fresh green coconuts are selected, ensuring that they are clean, undamaged, and microbiologically safe.
2. Extraction of Coconut Water
Coconut water is extracted under hygienic conditions. The inner pulp may optionally be included to enhance nutritional value.
3. Filtration
The extracted liquid is filtered using a fine mesh or muslin cloth to remove fibers and suspended solids.
4. Pasteurization
The filtered coconut water is pasteurized at 70–75°C for 20–30 minutes. This thermal pre-treatment ensures microbial stability and enzyme inactivation without causing significant degradation of heat-sensitive compounds.
5. Concentration by Rotary Vacuum Evaporation
The pasteurized coconut water is subjected to rotary vacuum evaporation at 45–50°C under a vacuum pressure of 200–250 mbar. This condition lowers the boiling point of water, thereby enabling concentration with minimal nutrient loss.
6. Determination of Endpoint
The process is continued until a total soluble solids content of 20–25°Brix is achieved, depending on intended application.
7. Packing and Storage
The concentrate is packed under aseptic conditions in sterile containers and stored under ambient or refrigerated conditions.
The final coconut water concentrate demonstrated improved sensory qualities such as clear color, pleasant aroma, and natural taste—meeting consumer expectations for freshness and purity. These improvements, combined with retained nutritional value, make the product suitable for various functional beverage applications.
The concentrate can be used as a base for health drinks, natural sweeteners, or ingredients in smoothies, sports beverages, and nutraceutical formulations. Its concentrated form allows for longer shelf life and ease of distribution in regions with limited cold chain infrastructure.
In conclusion, this invention presents a specialized, low-temperature, rotary vacuum evaporation method for producing high-quality coconut water concentrate. The process preserves essential nutrients, enhances shelf life, and delivers a clean-label, minimally processed solution that aligns with modern consumer demands for plant-based, functional beverages.
Experimental data:
1. pH and Titratable Acidity:
The pH of the rotary vacuum evaporated coconut water concentrate was recorded at 4.609, indicating stable acidity and minimal degradation of organic acids. The titratable acidity was found to be 0.1217%, showing balanced acid levels favorable for product stability and microbial safety.
2. Reducing and Non-Reducing Sugars:
Rotary vacuum evaporated samples retained a higher level of reducing sugars, indicating minimal breakdown of simple sugars under low-temperature conditions. Non-reducing sugars also remained stable, reflecting effective preservation of carbohydrate quality in the concentrate.
3. Vitamin C Content:
Vitamin C content was well preserved in the rotary vacuum evaporated samples due to the gentle processing temperature of 45–50°C under reduced pressure. This helped minimize thermal degradation and retain more of the naturally occurring ascorbic acid.
4. Antioxidant Activity (DPPH Method):
Rotary vacuum evaporated samples demonstrated strong antioxidant activity, with an average DPPH inhibition of 94.71%. This high level of free radical scavenging indicates that the rotary vacuum method is effective in preserving antioxidant compounds naturally present in coconut water.
5. Total Phenolic Content (TPC – Folin–Ciocalteu Method):
TPC was measured at 765 nm using the Folin–Ciocalteu method. Rotary vacuum evaporated samples showed absorbance values ranging from 0.31 to 0.47, indicating effective retention of phenolic compounds. Sample 4 exhibited the highest phenolic content, confirming the protective role of low-temperature evaporation on bioactive phytochemicals.
 
, Claims:1. A process for preparing coconut water concentrate, comprising:
a) selecting fresh green coconuts and hygienically extracting coconut water;
b) filtering the extracted coconut water to remove fibers and suspended solids;
c) pasteurizing the filtered coconut water at a temperature of 70–75°C for 20–30 minutes;
d) subjecting the pasteurized coconut water to rotary vacuum evaporation at a temperature of 45–50°C under a vacuum pressure of 200–250 mbar; and
e) concentrating the coconut water until a total soluble solids content of 20–25°Brix is obtained, thereby producing a stable coconut water concentrate.
2. The process as claimed in claim 1, wherein the rotary vacuum evaporation is carried out under conditions that retain the natural color, aroma, and flavor of the coconut water.
3. The process as claimed in claim 1, wherein the coconut water concentrate exhibits antioxidant activity with DPPH inhibition of 94.71%..
4. The process as claimed in claim 1, wherein the concentrate retains vitamin C content at levels higher than concentrates obtained using conventional thermal concentration methods.
5. The process as claimed in claim 1, wherein the pasteurization step ensures microbial stability without significant degradation of phenolic compounds.
6. The coconut water concentrate obtained by the process of claim 1, wherein the concentrate is formulated as an ingredient for functional beverages, nutraceutical formulations, sports drinks, or natural sweeteners.
7. A coconut water concentrate composition, comprising:
total soluble solids in the range of 20–25°Brix;
a pH of about 4.6;
titratable acidity of about 0.12%;
vitamin C content retained at levels higher than thermally concentrated coconut water;
antioxidant activity with DPPH inhibition of about 94–95%; and
total phenolic content in the range of 0.31–0.47 absorbance units;
wherein the concentrate retains natural flavour, aroma, and colour, and is adapted for incorporation into functional beverages, nutraceutical formulations, sports drinks, or natural sweeteners.