Stability assessment of virgin coconut oil-based emulsion products

In recent years, there has been dramatic growth in the market for virgin coconut oil (VCO). VCO, a promising functional food oil, has gained popularity and captured public attention worldwide. Two VCO‐based emulsion products were developed as a new nutritional food supplement with the aim of increasing the consumption of VCO. The stability of VCO‐based emulsion products was assessed during a storage period of 3 months to gauge the quality of the optimized VCO‐based emulsions. The particle‐size distributions of the VCO‐based emulsions remained stable throughout the 3‐month storage period at 25 and at 50°C. However, a slight increase in the particle sizes was observed in the VCO‐based emulsions samples after 2 months of storage at 4 °C. Nevertheless, phase separation did not occur in either of the VCO‐based emulsions products throughout the storage‐stability assessment period. No signs of microbial growth were detected in the emulsion products during the storage period. Furthermore, no significant changes in the free fatty acid contents of the emulsion products were observed during storage at 4 or 25°C throughout the storage period. The VCO‐based emulsion products possessed sufficient emulsion stability to withstand changes at different storage temperatures

Quality profile determination of palm olein: potential markers for the detection of recycled cooking oils

In this study, the safety and quality of commercial cooking oils were evaluated. The emphasis of this evaluation was on the presence of oxidation and polymerization products in fresh oils, although the analyses were often conducted on used frying fats and oils. This was because polymerized triacylglycerols (PTGs) and monomeric oxidized triacylglycerols (oxTAGs) have been proposed as potential indicators of the adulteration of palm olein. The oil quality was evaluated based on PTG content, the presence of epoxy, keto, and hydroxy acids, fatty acid composition, and smoke point. Principal component analysis (PCA) was conducted to identify the relationships among the analytical parameters. The total polar compound content of all fresh oil samples was within the safety limit for human consumption (< 25% polar compounds). TAG oligomers or epoxy, keto, or hydroxy acids were not detected in any of the fresh oil samples. Most of the packet oils had lower smoke point (< 200 °C) and linoleic acid content than the bottled oils. The pure palm olein samples were found to be better in terms of overall oil quality, as indicated by the PCA biplots of all analytical parameters. Abbreviations: ANOVA: analysis of variance; BPO: blended palm olein; DAG: diacylglycerol; FAME: fatty acid methyl ester; FFA: free fatty acid; HPLC: high-performance liquid chromatography; HPSEC: high-performance size exclusion chromatography; PC: principal component; PO: packet pure palm olein; PPO: pure palm olein; PCA: principal component analysis; SPE: solid-phase extraction; TAG: triacylglycerol; TPC: total polar compoun

New insights on degumming and bleaching process parameters on the formation of 3-monochloropropane-1,2-diol esters and glycidyl esters in refined, bleached, deodorized palm oil

This paper examines the interactions of degumming and bleaching processes as well as their influences on the formation of 3-monochloropropane-1,2-diol esters (3-MCPDE) and glycidyl esters in refined, bleached and deodorized palm oil by using D-optimal design. Water degumming effectively reduced the 3-MCPDE content up to 50%. Acid activated bleaching earth had a greater effect on 3-MCPDE reduction compared to natural bleaching earth and acid activated bleaching earth with neutral pH, indicating that performance and adsorption capacities of bleaching earth are the predominant factors in the removal of esters, rather than its acidity profile. The combination of high dosage phosphoric acid during degumming with the use of acid activated bleaching earth eliminated almost all glycidyl esters during refining. Besides, the effects of crude palm oil quality was assessed and it was found that the quality of crude palm oil determines the level of formation of 3-MCPDE and glycidyl esters in palm oil during the high temperature deodorization step of physical refining process. Poor quality crude palm oil has strong impact towards 3-MCPDE and glycidyl esters formation due to the intrinsic components present within. The findings are useful to palm oil refining industry in choosing raw materials as an input during the refining process

Principle component analysis of organoleptic acceptability on Cocos™ emulsion product

Cocos™ Emulsion is new food emulsion product that made of virgin coconut oil (VCO). A sensory analysis was conducted among targeted consumers, which were 150 schoolchildren (age 4 - 12) and 100 adult panelists (age 21 - 60). The principle component analysis (PCA) was applied to assess the organoleptic acceptability of public and schoolchildren on this novel product. In summary, both adult and schoolchildren panelists showed a significant preference (P < 0.05) toward Cocos™ Emulsion than VCO for both sensory attributes of taste and odour, as it was palatable. The scores plot of sensory attributes among all panelists were found highly scattered around, indicating no age-dependent preference on the sensory rating of each attributes

Mitigation of 3-MCPD esters and glycidyl esters during the physical refining process of palm oil by micro and macro laboratory scale refining

The reduction of the 3-monochloropropane-1,2-diol esters (3-MCPDE) and glycidyl esters (GE) was successfully achieved by the optimization of four processing parameters: phosphoric acid dosage, degumming temperature, bleaching earth dosage, and deodorization temperature by response surface methodology without the need for additional processing steps. The optimized processing conditions were 0.31% phosphoric acid dosage, 50 °C degumming temperature, 3% bleaching earth dosage, and 240 °C deodorization temperature. The optimization resulted in more than 80% and 65% reduction of 3-MCPDE and GE levels, respectively with color and FFA contents maintained in the acceptable range specified by Palm Oil Refiners Association of Malaysia. The optimized refining condition was transferred to macro scale refining units of 1 kg and 3 kg capacities to investigate its successful application during scale-up process

Influence of carbohydrate- and protein-based foods on the formation of polar lipid fraction during deep-frying

The extents of the oxidation and polymerization processes were examined in refined, bleached, and deodorized palm olein (RBDPO) to determine the impact of frying different foods on frying oil stability, particularly the formation of polar lipid fraction and short chain fatty acid upon frying, and at the same time to evaluate its discarding point. Sliced potatoes (SP) and chicken breast meat (CBM) were fried for 200 min/day for seven consecutive days using RBDPO at 180 °C without any oil replenishment. The amounts of total polar compound (TPC), polymerized triacylglycerols (PTG), and short-chain fatty acid (caprylic acid) that formed were significantly (p 25% polar compounds) on the seventh day of frying. In addition, the amounts of epoxy, keto, and hydroxy acids that formed were significantly (p < 0.05) higher in the RBDPO used to fry CBM compared to SP. RBDPO also exceeded the safety limit when the concentration of epoxy acids respectively reached 7.4 g/kg and 8.8 g/kg after frying SP and CBM for seven days

Development of Virgin Coconut Oil (VCO) based emulsion product as dietary supplement

Recently, the demand of virgin coconut oil (VCO) among public continues to rise due to its superior flavour and also its potential health benefits. The present study reports on the development of a VCO-based emulsion product as a dietary supplement. This study is divided into four major parts, namely, the characterisation of commercial food supplement emulsions, the development of VCO-based emulsion formulations, storage stability studies using optimised VCO-based emulsion, and lastly a sensory assessment of an optimised VCO-based emulsion. In the product characterisation study, the physicochemical properties of the commercial emulsion products (C1, C2, C3, and C4) were investigated. C3 exhibited the smallest particle size at 3.25 μm. The pH for the emulsion samples ranged between 2.52 and 3.45 and were thus categorised as acidic. In a texture analysis, C2 was described as the most firm, it was very adhesive and cohesive, and it had high compressibility properties. From a rheological viewpoint, all the emulsion samples exhibited non-Newtonian behaviour, which presented as a shear-thinning property. In this context, the zeta potential of the commercial emulsion samples ranged between -23.17 mV and -52.77 mV. C2 exhibited the highest percentage of fat (18.44%) among all the emulsion samples. During the formulation development of full factorial studies, the influences of different levels of formulation variables, namely the gum arabic concentration (0.75-1.75%, w/v), the xanthan gum concentration (0.8-1.0%, w/v), the VCO concentration (10-20%, v/v), and the maltodextrin concentration (1-3%, w/v) on the pH, particle size, emulsion stability index (ESI), and rheological study of the VCO-based emulsion were studied. All the formulation parameters significantly (p 0.05) changes in the free fatty acid contents of the emulsion products were observed during storage at 4°C or 25°C throughout the storage period. A sensory assessment among UPM students showed that for the flavouring preference, both 7.5% and 10% VCO emulsion products showed significant differences (p < 0.05) in terms of odour, taste, sweetness, and overall acceptability, and most of the panellists preferred mango flavouring. Among all the emulsion samples, the 7.5% VCO emulsion with mango flavouring yielded the best sensory score with all the sensory attributes scoring more than 5. For the public consumer sensory evaluation, the significant preference towards the VCO emulsion relative to VCO alone also supported the potential to market the VCO emulsion to increase VCO consumption among consumers

Evaluation and development of quality indices for adulteration in palm oil industry by used and recycled oils

Currently, recycled oil has emerged as a prominent food safety issue and poses a major threat to the public health. Various studies have been conducted to detect the adulteration of used and recycled palm olein in refined, bleached, and deodorized palm olein (RBDPO). The presence of polymerized triacylglycerols (PTGs), monomeric oxidized triacylglycerols (oxTAGs), or caprylic acid (C8:0) has been proposed as a potential indicator to track the adulteration. Therefore, this study investigates the presence of these compounds in commercial cooking oils, their formation during various heating and deepfrying studies, and their presence in recycled oil samples. This study can be used to justify the suitability of these compounds for use as the quality indicators to trace the adulteration of used or recycled oil. In the first part of this study, a total of 23 commercial cooking oil samples were purchased from a market in Malaysia and were categorized into three main groups, namely, pure palm olein, blended palm olein, and packet oil. The total polar compounds (TPCs) for all fresh oil samples were within the safety limit for human consumption (< 25% polar compounds) set in many European countries. No triacylglycerol (TAG) oligomers, epoxy-, keto-, or hydroxy acids were detected in any of the fresh oil samples. In the second part of this study, a controlled heating study was carried out, RBDPO was heated continuously for 24 h at 160 °C, 170 °C, and 180 °C, with the oil sampled at 4- hour intervals. The oxTAG, TPC, and PTG concentrations in RBDPO increased significantly (p<0.05) with the temperature and heating time. At the end of the heating study, more epoxy acids were formed compared to keto and hydroxy acids. However, the TPC exceeded the limit of rejection for human consumption (>25% polar compounds). Moreover, caprylic acid, which was not present in fresh oil, was formed in significant amounts after the controlled heating study. In the third part of this work, two different types of food products, namely, sliced potato (SP) and chicken breast meat (CBM) were fried in a total duration of 200 min/day for seven consecutive days using RBDPO at 180 °C without any oil replenishment. The amounts of TPC, PTG, and caprylic acid that formed were significantly (p < 0.05) higher in the RBDPO used to fry SP compared to that used for CBM. The TPC in the RBDPO used to fry SP exceeded the limit of rejection for human consumption (> 25% polar compounds) on the seventh day of frying. In addition, the amounts of epoxy, keto, and hydroxy acids that formed were significantly (p < 0.05) higher in the RBDPO used to fry CBM compared to that used for SP. Following this, oil samples that underwent controlled heating and deep-frying studies were refined using the common oil refining procedure to simulate the production of recycled oil. PTG, TAG oligomers and dimers showed a significant increase (p < 0.05) after the refining process. The oxTAG, free fatty acid (FFA), peroxide value (PV), and p-anisidine value (AV) dropped significantly (p < 0.05) in the recycled RBDPO after the refining process. For the last part of the study, FT-NIR spectroscopy coupled with chemometrics was used to rapidly quantify the amount of thermo-oxidative products such as PTG, oxTAG, and TPC formed in used frying oil. Three separate partial least squares regression (PLS) models were built with high calibration accuracy. In conclusion, the few proposed potential quality indicators, namely PTG, oxTAG, and caprylic acid, were all detected in recycled oil. These findings justified the suitability of these parameters to be used in the quality indices to trace the adulteration of cooking oil as these compounds were not detected in the fresh oil. It is our hope that the findings of this study will be able to control the adulteration of used and recycled palm olein in RBDPO for the protection of the health and safety of consumers

Formation of 3-MCPD and glycidyl esters in biscuits produced using soybean oil-based diacylglycerol stearin-shortening blends: impacts of different baking temperatures and blending ratios

Diacylglycerol (DAG) is commonly known as one of the precursors for 3-monochloropropane-1,2-diol esters (3-MCPDE) and glycidyl esters (GE) formation. Besides, 3-MCPDE and GE are heat-induced contaminants which can be formed in fat-containing baked products during the baking process. This study attempted to replace the conventional palm-based shortening (SH) with a healthier fat, namely soybean oil-based diacylglycerol stearin (SDAG) in producing biscuits. The effects of different baking temperatures (200, 210 and 220 °C) and SDAG:SH fat blend ratios (0:100, 60:40 (D64S), 80:20 (D82S), 100:0, w/w) towards the biscuits’ physical properties were evaluated. Moreover, the oxidative stability, 3-MCPDPE and GE formation in the fats extracted from the biscuits were also investigated. SDAG-produced biscuit showed slight reductions in the spread ratio compared to the SH-produced biscuit. The elevated baking temperatures resulted in biscuits with increased hardness and low moisture content. Pure SDAG and the other fat blends exhibited significant (p < 0.05) poorer oxidative stability than SH. However, D64S was found to be more oxidative stable compared to SDAG and D82S. The D64S fat blend exhibited the lowest 3-MCPDE and GE formation rates among all fat samples with the increasing baking temperatures. Furthermore, the amount of 3-MCPDE and GE detected in the fats extracted from the biscuits baked at highest temperature (220 °C) were still within the safety limit. In overall, better quality biscuits were produced when lower baking temperature (200 °C) was used as all biscuits baked with different fats showed similar textural properties (hardness and cohesiveness), higher oxidative stability and lower formation of 3-MCPDE and GE compared to biscuits baked at higher temperatures. The findings justified the potential of D64S fat blend in replacing the conventional SH in producing healthier biscuits

Evaluation of quality parameters for fresh, used and recycled palm olein

Background: Recycled oil has emerged as a significant food safety issue and poses a major threat to public health. To date, very limited studies have been conducted aiming to detect the adulteration of used and recycled palm olein in refined, bleached and deodorized palm olein (RBDPO). In the present study, oil samples that underwent controlled heating and deep-frying studies were refined using the common oil refining procedure to simulate the production of recycled oil. Polymerized triacylglycerol (PTG), oxidized monomeric triacylglycerols (oxTAGs), such as epoxy, keto and hydroxy acids, and caprylic acid have been proposed as potential indicators for tracking the adulteration of recycled oil. Results: For PTG, triacylglycerol oligomers and dimers showed a significant increase (P < 0.05) after the refining process. Although there was a significant reduction (P < 0.05) in the total oxTAGs concentration after refining, they were still present in the recycled palm olein, even though the used palm olein had undergone a complete oil refining process. The concentration of caprylic acid increased significantly (P < 0.05) in palm olein after undergoing various heat and deep-frying treatments and even showed a significant (P < 0.05) increase in recycled oil. Conclusion: The results obtained in the present study justify the suitability of the proposed quality parameters for use as quality indices with respect to controlling the adulteration of used and recycled palm olein in RBDPO for the protection of the health and safety of consumers. © 2019 Society of Chemical Industr