Heating and megasonic interventions for improvement of aqueous-based oil extraction from fresh and cold stored coconut meat

Multi-frequency ultrasonic-assisted enzymatic extraction of coconut paring oil from coconut by-products: Impact on the yield, physicochemical properties, and emulsion stability

Extraction of coconut paring oil (CPO) from processing by-products adds value to the product and reduces resource wastage. This study aims to assess the impact of 20 kHz, 20/80 kHz and 20/40/80 kHz of multi-frequency ultrasonic-assisted enzymatic extraction (MFUAEE) on the yield, physicochemical properties, fatty acid composition, total phenolic content, antioxidant activity, and emulsion stability of CPO derived from wet coconut parings (WCP). Results revealed that the CPO extraction yield with MFUAEE was 32.58 % - 43.31 % higher compared to AEE. The tri-frequency 20/40/80 kHz mode of multi-frequency ultrasound pretreatment exhibited the highest CPO extraction yield (70.08 %). The oil extracted through MFUAEE displayed similar fatty acid profiles to AEE, but had lower peroxide value, K232 and K270 values. Particularly, MFUAEE oil contained higher total phenolic content and exhibited potent DPPH free radical scavenging capacity. Results observed by SEM indicated that the pretreatment with multi-frequency ultrasound more efficiently disrupts the cellular structure of the WCP. Additionally, MFUAEE enhanced emulsion stability through the cavitation effect of ultrasound. These findings suggest that MFUAEE is a valuable approach for method for obtaining CPO with elevated extraction yield and superior quality, thereby enhancing the utilization of coconut by-products.

Family 3 CBM improves the biochemical properties, substrate hydrolysis and coconut oil extraction by hemicellulolytic and holocellulolytic chimeras

To understand the influence of family 3 Carbohydrate Binding Module (hereafter CBM3), single (GH5 cellulase; CelB, CelBΔCBM), bi-chimeric [GH26 endo-mannanase (ManB-1601) and GH11 endo-xylanase (XynB); ManB-XynB [1], ManB-XynB-CBM] and tri-chimeric [ManB-XynB-CelB [1], ManB-XynB-CelBΔCBM] enzyme variants (fused or deleted of CBM) were produced and purified to homogeneity. CBM3 did not alter the pH and temperature optima of bi- and tri-chimeric enzymes but improved the pH and temperature stability of ManB in CBM variants of bi-/tri-chimeric enzymes. Truncation of CBM in CelB shifted the pH optimum and increased the melting temperature (Tm 65 ℃). CBM3 improved both substrate affinity (Km) and catalytic efficiency (kcat/Km) of fused enzymes in tri-chimera and CelB but only Km for bi-chimera. Far-UV CD of CelB and bi- and tri-chimeric enzymes suggested that CBM3 improved the α-helical content and compactness in the native state but did not prevent disintegration of secondary structural contents at acidic pH. Steady-state fluorescence studies suggested that under acidic conditions CBM3 prevented the exposure of hydrophobic patches in bi-chimeric protein but could not avert the opening up of chimeric enzyme structure. Aqueous enzyme assisted treatment of mature coconut kernel using single, bi- and tri-chimeric enzymes led to cracks, peeling and fracturing of the matrix and improved the oil yield by up to 22%.

Impact of thermal and nonthermal process intensification techniques on yield and quality of virgin coconut oil

Virgin coconut oil (VCO) is valued for its nutraceutical potential. The focus of this research was to assess the effect of selected thermal and nonthermal pre-treatments on the yield and quality of subsequently wet-extracted VCO. The fresh coconut cream was subjected to microwave heating (450 W, 2 min), ohmic heating (180 V, 5 min), ultrasonication (350 W, 10 min), or a pulsed electric field (40 kV cm-1, 12.32 min). The thick cream was separated, and VCO was obtained after a freeze-thaw process. The highest VCO yields (>93%) were observed in the cases of ultrasonicated and pulsed electric field-treated samples. A range of oil quality parameters, total phenolic content, and antioxidants were evaluated. Further, the fatty acid composition of all oils was studied. Observations from this research indicate that ultrasonication pre-treatment resulted in the best VCO yield and quality.

Innovative technologies to enhance oil recovery

The processes for extracting and refining edible oils are well-established in industry at different scales. However, these processing lines encounter inefficiencies and oil losses when recovering crude or refined oil. Palm oil and olive oil extraction methods are used mainly as a combination of physical, thermal, and centrifugal methods to recover crude oil, which results in oil losses in the olive pomace or in palm oil effluents. Seed oils generally require a seed steam conditioning, and cooking stage, followed by physical oil recovery through an inefficient expeller. Most of the crude oil remaining in the expeller cake is then recovered by hexane. Crude seed oil is further refined in stages that also undergo oil losses. This chapter provides an overview of innovative technologies using microwave, ultrasound, megasonic and pulsed electric field energies, which can be used in the above-mentioned crude and refined oil processes to improve oil recovery. This chapter describes traditional palm oil, olive oil, and seed oil processes, as well as the specific process interventions that have been tested with these technologies. The impact of such technology interventions on oil quality is also summarized.

Novel application of ultrasound and microwave-assisted methods for aqueous extraction of coconut oil and proteins

Alternative methods for wet extraction of coconut oil and protein assisted by ultrasound or microwave were developed and compared. Coconut milk was prepared by milling the pulp (5:1 water to coconut pulp ratio), further destabilised at pH 4 and centrifuged to obtain the cream and cream protein fractions (control process). Microwave-assisted treatment applied in milk (1 min, 3 pulses of 20 s; 2.5 GHz; 4.31 kW/kg by pulse) generated a significant increase in cream obtained, and in the coconut oil extraction yield (~ 20%) compared to its control. The ultrasound-assisted treatment (2.5 min; 24 kHz; 0.573 kW/kg, 6.85 W/cm2) also improved oil extraction (10-16%). Moreover, a higher protein yield was achieved in ultrasound treated samples when compared to their control (49.6-86.1%). Large particles of 11 m μ , probably aggregates of particles, and smaller particles of 3.6 m μ , were detected in coconut milk, which were reduced by ultrasound effect. Alternative treatments caused a greater liberation of total phenols in coconut cream. Coconut proteins in water (0.1%) showed high negative electrokinetic potential. The surface pressure of coconut proteins at the air/water interface was not modified by assisted treatments.

A comprehensive review on the techniques for coconut oil extraction and its application

Virgin coconut oil is a useful substance in our daily life. It contains a high percentage of lauric acid which has many health benefits. The current industry has developed several methods to extract the oil out from the coconut fruit. This review paper aims to highlight several common extraction processes used in modern industries that includes cold extraction, hot extraction, low-pressure extraction, chilling, freezing and thawing method, fermentation, centrifugation, enzymatic extraction and supercritical fluid carbon dioxide. Different extraction methods will produce coconut oil with different yields and purities of lauric acid, thus having different uses and applications. Challenges that are faced by the industries in extracting the coconut oil using different methods of extraction are important to be explored so that advancement in the oil extraction technology can be done for efficient downstream processing. This study is vital as it provides insights that could enhance the production of coconut oil.

Application of high-frequency ultrasound standing waves for the recovery of lipids from high-fat dairy effluent

Effect of high-frequency ultrasonication was examined on wastewater of a cheese manufacturing plant. Tests were carried out at two frequencies (500 kHz and 1 MHz) and two temperatures (22 and 40 °C). Samples were subjected to different energy densities; 7.5, 30.2, 60.5 and 121.0 J/mL at 500 kHz and 7.9, 31.7, 63.4 and 126.8 J/mL at 1 MHz to observe the creaming and recovery of lipid. These energy densities correspond to 30, 120, 240 and 480 s of sonication. Sonication was performed using a single plate transducer and reflector system at 40 W to create standing wave to coalesce and flocculate lipid globules. Recovery was higher at 40 °C after 480 s of sonication at both frequencies (77% at 500 kHz and 75% at 1 MHz). The lowest recovery of 47% was observed at 500 kHz and 22 °C at all applied energy densities. Changes in particle size and turbidity in the bottom aliquot indicated that high-frequency ultrasound caused coagulation and aggregation and settling of colloidal particles. Increase in particle size was observed to be highest at 1 MHz, 40 °C and 480 s of sonication. These results confirm that high-frequency ultrasound standing wave technology can be used to recover lipid from high-lipid dairy wastewater including that from cheese manufacturing.

Sono-physical and sono-chemical effects of ultrasound: Primary applications in extraction and freezing operations and influence on food components

Ultrasound is an advanced non-thermal food-processing technology that has received increasing amounts of interest as an alternative to, or an adjuvant method for, conventional processing techniques. This review explores the sono-physical and sono-chemical effects of ultrasound on food processing as it reviews two typical food-processing applications that are predominantly driven by sono-physical effects, namely ultrasound-assisted extraction (UAE) and ultrasound-assisted freezing (UAF), and the components modifications to food matrices that can be triggered by sono-chemical effects. Efficiency enhancements and quality improvements in products (and extracts) using ultrasound are discussed in terms of mechanism and principles for a range of food-matrix categories, while efforts to improve existing ultrasound-assist patterns was also seen. Furthermore, the progress of experimental ultrasonic equipments for UAE and UAF as food-processing technologies, the core of the development in food-processing techniques is considered. Moreover, sono-chemical reactions that are usually overlooked, such as degradation, oxidation and other particular chemical modifications that occur in common food components under specific conditions, and the influence on bioactivity, which was also affected by food processing to varying degrees, are also summarised. Further trends as well as some challenges for, and limitations of, ultrasound technology for food processing, with UAE and UAF used as examples herein, are also taken into consideration and possible future recommendations were made.

Direct infusion electrospray ionisation mass spectrometry applied in the detection of adulteration of coconut oil with palm kernel oil

Coconut oil has properties that are beneficial to human health. It assists in reducing total cholesterol, triacylglycerol (TAG), phospholipids, low-density lipoprotein (LDL) cholesterol, and very low-density lipoprotein (VLDL) cholesterol in serum and tissues. So its production, and consequently consumption, have increased in recent years. However, it has been a target for intentional adulteration with lower priced oils and fats, such as soybean oil and palm kernel oil (PKO). Coconut oil (CO) and PKO have similar chemical and physical characteristics that make it difficult to verify adulteration of CO with PKO. This study demonstrates a simple, sensitive, and fast technique that uses direct infusion electrospray ionisation mass spectrometry (ESI-MS) in conjunction with principal component analysis (PCA), in order to detect CO adulterated with PKO. Among the seven commercial coconut oil samples analysed, three were adulterated with PKO. Therefore, the suggested direct infusion ESI-MS method can be used in routine analysis to guarantee the quality of coconut oil.

Impact of sound attenuation on ultrasound-driven yield improvements during olive oil extraction

High frequency ultrasound can enhance olive oil extractability industrially. However, the ultrasound attenuation phenomena and their implications on extractability, are not well understood. This work aims at evaluating the ultrasound attenuation effects on the oil extraction efficiency, while providing deeper insights into the physics behind the ultrasound extraction in a heterogeneous medium. Olives were collected and processed both in Italy and Uruguay during their respective harvest seasons. Sound pressure distribution was characterized in a high frequency ultrasound reactor, carrying 3 kg of water or paste, by using an indirect contact hydrophone device at 0.4 MHz or 2 MHz. A through-transmission ultrasonic technique was applied to determine attenuation profiles and coefficients in paste at the central frequency of each transducer, with various paste to water ratios and reactor sizes. Other ultrasound improvements on extractability were evaluated including reduction of malaxation time (10, 30 min), sonication time (2.5, 5 min) and power level (174, 280 W) without water addition and in a reactor with a 14.5 cm transducer to wall distance. However, no sound pressure levels in paste were detectable beyond 9 cm from the transducer at both frequencies. Among the various effects evaluated, an emission frequency of 0.4 MHz better improved extractability compared to 2 MHz. The attenuation profiles corroborated these findings with attenuation coefficients of 3.9 and 5.3 dB/cm measured near the respective frequencies. Improvements in oil extractability due to increasing sonication time and power level were significant (p < 0.05) also when sonicating beyond 14.5 cm and without water addition. Oil extractability improvements were observed even when sound pressure was undetectable beyond 9 cm from the transducer, suggesting that the standing wave oil trapping effect is not the governing mechanism for separation in high attenuation media for large scale systems.

Phase separation technology based on ultrasonic standing waves: A review

The current understanding and developments of phase separation technology based on ultrasonic standing waves (USWs) are reviewed. Most previous reviews have focused on microscale applications of this technology in the fields of biological materials and food processing. This review covers different applications of ultrasonic separation technology, especially in petrochemical industry. The kinetic mechanism of ultrasonic, design of reactors, separation principles, and related applications are discussed in detail. We lay special stress on the motion characteristics of particles in USWs. According to the particle numbers, particle properties, and frequency characteristics, the separation principles are reasonably categorized as: (1) Bands effect; (2) Acoustophoretic coefficient; (3) Particle density; (4) Sweep frequency. Diverse separation principles improve the universality of ultrasonic separation technology. However, acoustic streaming and acoustic cavitation are two of the main challenges in the application of ultrasonic separation. Based on the current research, the future research can focus on the following aspects: (1) Explore the mechanism of ultrasonic demulsification; (2) Establish unified evaluation criteria for acoustic separation systems; (3) Develop the basis for determination of acoustic cavitation and non-cavitation.