Coconut (Cocos nucifera L.) is popularly known as the "Tree of Life," owing to the wide range of food and industrial uses. One of the central constituents of coconut products is coconut milk, valued for its rich flavour, creamy mouthfeel and nutritional properties. However, the manufacturing of virgin coconut oil (VCO) results in skimmed coconut milk, a defatted aqueous extract of coconut milk, that still contains considerable amounts of protein, carbohydrates, and minerals. In many cases, the removed coconut milk is not fully valued and simply thrown away, resulting in waste and unwanted environmental impact. By converting skimmed coconut milk into a ready-to-serve (RTS) coconut milk beverage, value addition in the coconut industry with functional and value-added beverage products can be achieved economically and sustainably. This approach aligns with current trends in beverage product development, drink formulation, and custom beverage development that utilize by-products to create novel functional beverages.[1]
Optimization of Retort Processing for Enhancing Shelf Stability in Ready-to-Serve Coconut Milk Beverages: A Beverage Formulation Approach
Coconut (Cocos nucifera L.) is popularly known as the “Tree of Life,” owing to the wide range of food and industrial uses. One of the central constituents of coconut products is coconut milk, valued for its rich flavour, creamy mouthfeel and nutritional properties. However, the manufacturing of virgin coconut oil (VCO) results in skimmed coconut milk, a defatted aqueous extract of coconut milk, that still contains considerable amounts of protein, carbohydrates, and minerals. In many cases, the removed coconut milk is not fully valued and simply thrown away, resulting in waste and unwanted environmental impact. By converting skimmed coconut milk into a ready-to-serve (RTS) coconut milk beverage, value addition in the coconut industry with functional and value-added beverage products can be achieved economically and sustainably. This approach aligns with current trends in beverage product development, drink formulation, and custom beverage development that utilize by-products to create novel functional beverages.[1]
Principle of Retort processing for RTS Coconut milk beverage:
The retort processing is carried out to preserve the unique nutritional composition. Coconut milk is containing medium chain triglycerides (MCT), protein, and fat globules under retort processing coconut milk, increases microbial safety, reduces protein denaturation and fat separation. So, this process preserves essential lipids, vitamins and minerals better than any other heat methods. The process is therefore an important element of beverage formulation and thermal treatment strategies used for dairy-alternative beverages. [2]
Coconut Milk Extraction and Retort Processing:
Origin and Characteristics of Coconut Milk
- The Asian food industry uses coconut milk as a fundamental ingredient which originates from mature coconut kernel grated material that can be extracted through manual or mechanical methods with or without water addition (de Leon and Delores, 2004).
- The combination of oil content and moisture levels and organic substances in fresh coconut milk makes it extremely short-lived because it becomes spoiled quickly through microbial growth and enzymatic reactions (Gonzalez, 1990).
- These characteristics require effective thermal processing optimization to ensure product safety and stability.
Thermal Processing for Shelf-Life Extension
- The application of thermal processing serves as a primary method to extend product shelf life.
- The production process for canned and retort-processed coconut milk starts with extraction followed by enzyme inactivation and microbial reduction at 92–95 °C for 5–20 minutes.
- The product receives emulsifiers and stabilizers for phase separation prevention before homogenization to achieve uniform consistency.[4]
Packaging and Classification of Coconut Milk
- The homogenized coconut milk receives packaging into heat-resistant containers which include tin cans and flexible retort pouches before the containers receive hermetic seals.
- The pH level of coconut milk at 6.0 classifies it as a low-acid food which needs retort sterilization at temperatures above 100 °C to eliminate Clostridium botulinum and other heat-resistant bacterial spores (Timmins and Kramer, 1977; Gonzalez, 1990; Arumughan et al., 1993).
Retort Processing Steps
- The sealed containers undergo retort processing by being placed in a pressurized vessel which uses steam or hot water to heat them to 115–121 °C for a specific time to achieve complete sterilization.
- The products undergo immediate cooling after sterilization to stop further cooking before they receive drying treatment and receive their labels and storage preparation.
Aseptic or UHT Processing Alternatives
- Coconut milk production through aseptic or ultra-high-temperature (UHT) processing methods enables sterile packaging without requiring in-container sterilization.
The safety of low-acid beverages which have a pH above 4.6 requires sterilization because coconut milk needs this method to become safe for consumption. The high-temperature pressure-assisted sterilization method known as retort processing serves the dairy and non-dairy beverage industry to create microbial stability while preserving both sensory attributes and nutritional values. This type of coconut milk beverage processing aligns with the industrial practices of maintaining quality in ready-to-serve coconut milk systems. The process ends with removal of the packaging followed by cooling and storage readiness. [3]
Optimal Retort Processing Conditions for Shelf-Stable Flavoured Skimmed Coconut Milk:
The best retort processing conditions for ready-to-serve flavoured skimmed coconut milk need to protect against microorganisms while preserving product quality. This is crucial in heat treatment for dairy alternatives, where protein stability is essential. Research has shown that the following processing conditions work successfully:
- The combination of 85°C heat for 30 minutes produced the highest sensory ratings for defatted coconut milk packaged in retort pouches which provided safe microbial conditions for 45 days when stored under refrigeration.
- The combination of 90°C heat for 15 minutes proved to be a reliable method for coconut milk preservation in glass and polypropylene bottles which enabled safe storage at room temperature for four months without major deterioration of product quality.
Effect of Retort Processing Conditions on Moisture Content and Shelf Life of Flavoured Skimmed Coconut Milk
This table highlights the effects of retort temperature and time on coconut milk beverage quality, focusing on moisture changes, stability and sensory attributes across various thermal treatments. [5]
Retort Temperature (°C) | Holding Time (min) | Initial Moisture Content (% w/w) | Moisture After Processing (% w/w) | Moisture After 6 Months Storage (% w/w) | Shelf Life (months) | Remarks |
80 | 10 | 86.2 ± 0.3 | 85.7 ± 0.4 | 85.3 ± 0.5 | 3 | Incomplete sterilization; microbial growth after 3 months |
85 | 20 | 86.1 ± 0.2 | 85.5 ± 0.3 | 85.1 ± 0.4 | 4 | Moderate shelf life; slight color change |
85 | 30 | 86.3 ± 0.2 | 85.4 ± 0.3 | 85.0 ± 0.3 | 6 | Optimal condition: good stability, acceptable sensory quality |
90 | 20 | 86.0 ± 0.3 | 85.2 ± 0.3 | 84.8 ± 0.4 | 6 | Stable product; minor flavor degradation |
95 | 30 | 85.9 ± 0.2 | 85.0 ± 0.3 | 84.6 ± 0.3 | 6 | Overprocessed; slight browning and cooked flavor |
Insights from Food Research Lab
- At Food Research Lab, we developed various functional beverages through advanced beverage product development, custom beverage development, and applied beverage formulation strategies. We have used retort processing technology to ready to drink beverages and milkshakes that contain functional ingredients.
- The core challenge in formulating RTD drink, milkshakes involves coagulation, protein denaturation, texture loss.
- All these were addressed by optimizing the retort processing temperature, time, homogenization to improve heat stability thereby maintaining product quality under thermal processing optimization.
Product Example:
Product name: Tasty nibbles coconut milk
Type: Beverage form
- Processed using advanced Japanese Retort technology.
- No refrigeration is required until opened.
- Guaranteed 24-month shelf life at room temperature.
- 100% convenience with zero wastage and FSSAI-approved.
Conclusion:
The safety and quality of ready-to-serve coconut milk beverages depend on proper retort processing optimization. Ensuring the right balance of heat treatment, formulation, and packaging is vital in coconut milk beverage processing and broader beverage product development.
To discover comprehensive formulation and testing solutions, connect with Food Research Lab. We provide end-to-end support in drink formulation, beverage formulation, physicochemical optimization, shelf-life assessment, and regulatory-compliant product standardization for successful commercialization.
Reference:
- CDF Corporation. (2023, May 10). Retort processing: What is retort processing? CDF Corporation. https://www.cdf1.com/what-is-retort-processing/ com
- PMG Engineering. (n.d.). Retort technology: Revolutionising food processing and preservation. PMG Engineering. https://pmg.engineering/Article/36/retort-technology-revolutionizing-food-processing-and-preservation/ PMG Engineering
- The Pharma Innovation Journal. (2019). Sahana, N., & Ramasamy, D. Process optimization and shelf life study of retort processed coconut milk. The Pharma Innovation Journal, 8(9), 134-136. https://www.thepharmajournal.com/archives/2019/vol8issue9/PartC/8-9-15-327.pdf
- Pulissery, S. K., Shahanas, E., Vithu, P., Boregowda, S. K., Kothakota, A., & Pandiselvam, R. (2023). Optimization of retort processing parameters for the production of ready-to-serve flavored skimmed coconut milk. Journal of Culinary Science & Technology, 23(1), 71-86. https://doi.org/10.1080/15428052.2023.2182247
- Siriphanich, J., Saradhuldhat, P., Romphophak, T., Krisanapook, K., Pathaveerat, S., & Tongchitpakdee, S. (2011). Coconut (Cocos nucifera). In Postharvest biology and technology of tropical and subtropical fruits: Cocona to mango (pp. 8–33, 34e–35e). Woodhead Publishing. https://doi.org/10.1533/9780857092885.8
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