Detection and determination of furfural in crude palm oil.

In the palm oil mill, fresh fruit bunch (FFB) undergoes various thermal and mechanical treatments to produce the crude palm oil (CPO). FFB consists of many fruits attached to the spikelets that are spirally arranged on the main bunch stalk. Each fruit is made up of a nut enveloped by the fleshy mesocarp, which is reinforced by strands of fibers running from the base towards the fruit tip. A ripe fruit mesocarp contains oil-rich cellulosic cells. These cells are bound together by hemicellulose. Whilst cellulose is very stable, the hemicellulose is easily hydrolyzed. This hydrolysis occurs during sterilization of the FFB when it is exposed to temperatures of 140-145°C and pressure of 40-45 pound per square inch (psi) or 275.8-310.3 kPa for 1-1½ hours. This condition aims at and ensures the detachment of fruits from the bunch. The in-depth chemical changes that occur in the FFB during sterilization are not fully understood and continuously being investigated. Xyloses form one of the products of hydrolysis, and furfural is another product that results from the dehydration of pentose formed also upon the hydrolysis of hemicellulose. Presence of furfural was tested in six extracted samples, namely CPO, mill-pressed crude, condensate oil, sludge oil, sterilized FFB oil and unsterilized FFB oil, using aniline acetate colorimetric method, thin-layer chromatography (TLC) and UV-visible spectrophotometry. The color formation was compared to that of standard furfural. Furfural was detected in CPO, crude, condensate oil, sludge oil and sterilized FFB oil, while it was undetected in the unsterilized FFB. The amount of furfural was quantified in CPO, condensate oil and sludge oil using high-performance liquid chromatography (HPLC)

Essential fatty acids of pitaya (dragon fruit) seed oil

Hylocereus undatus and Hylocereus polyrhizus are two varieties of the commonly called pitaya fruits. The seeds were separated and the oil was extracted and analysed. Essential fatty acids, namely, linoleic acid and linolenic acid form a significant percentage of the unsaturated fatty acids of the seed oil extract. Both pitaya varieties exhibit two oleic acid isomers. Essential fatty acids are important acids that are necessary substrates in animal metabolism and cannot be synthesised in vivo. Both pitaya varieties contain about 50% essential fatty acids (C18:2 (48%) and C18:3 (1.5%)). This paper details the process of recovering the pitaya seeds and determining the composition of the oil extracted from the seeds

Pretreatment with a Heat-Killed Probiotic Modulates the NLRP3 Inflammasome and Attenuates Colitis-Associated Colorectal Cancer in Mice.

Colorectal cancer (CRC) is one of the most common malignancies worldwide. Inflammation contributes to cancer development and inflammatory bowel disease is an important risk factor for CRC. The aim of this study is to assess whether a widely used probiotic Enterococcus faecalis can modulate the NLRP3 inflammasome and protect against colitis and colitis-associated CRC. We studied the effect of heat-killed cells of E. faecalis on NLRP3 inflammasome activation in THP-1-derived macrophages. Pretreatment of E. faecalis or NLRP3 siRNA can inhibit NLRP3 inflammasome activation in macrophages in response to fecal content or commensal microbes, P. mirabilis or E. coli, according to the reduction of caspase-1 activation and IL-1β maturation. Mechanistically, E. faecalis attenuates the phagocytosis that is required for the full activation of the NLRP3 inflammasome. In in vivo mouse experiments, E. faecalis can ameliorate the severity of intestinal inflammation and thereby protect mice from dextran sodium sulfate (DSS)-induced colitis and the formation of CRC in wild type mice. On the other hand, E. faecalis cannot prevent DSS-induced colitis in NLRP3 knockout mice. Our findings indicate that application of the inactivated probiotic, E. faecalis, may be a useful and safe strategy for attenuation of NLRP3-mediated colitis and inflammation-associated colon carcinogenesis

Application of headspace solid-phase microextraction and gas chromatography for the analysis of furfural in crude palm oil

Processing of vegetative material containing pentoses has been shown to result in the formation of furfural. Furfural exhibits a spectrophotometric absorption peak at 518 nm when complexed with aniline acetate. Headspace solid-phase microextraction (HS-SPME) method has been successfully used to confirm the presence of furfural in crude palm oil (CPO). Solid phase microextraction (SPME) fiber composed of divinylbenzene/Carboxen/polydimethylsiloxane (DVB/PDMS/CAR) was used to absorb the volatiles in the headspace of the oil. The isolated compounds from the fiber was desorbed and separated on a capillary polar column of a gas chromatograph. Response surface methodology (RSM) was used to optimize the SPME fiber condition for maximum absorption of furfural from CPO. The optimized temperature and time for furfural extraction onto the SPME fiber are 70 °C for 40 min. Oils obtained from the mill were found to contain between 2 and 13% furfural

Monoglyceride-based emulsifier technology to enhance emulsion stability in milk coffee beverages

Milk coffee beverages are a protein-stabilised emulsion and consist of dispersed oil droplets in the aqueous phase. Casein, whey proteins and mono- and diglycerides (MDGs) are surface-active agents that adsorb at the oil-water interface to form and stabilise emulsions. Protein is an important natural emulsifying agent in emulsion systems and interact with MDGs at the oil-water interface to modify oil droplet size, zeta potential, flow behaviour, physical stability and oxidative stability. Many studies have investigated the interaction between milk protein and MDG and their effect on droplet properties, flow behaviour and food structure in whippable emulsions. However, there is very little knowledge around the interaction of MDG and milk protein in beverage emulsions. MDG is an oil-soluble emulsifier and has low solubility in water, making it not suitable for direct application in many food formulations. Encapsulation of MDG could be a potential solution to convert it into a stable water-dispersible powder; however, there is very little information published about the encapsulation of emulsifiers as a functional ingredient. This project had two main objectives. The first objective aimed to gain fundamental understandings on the effect of MDG and milk protein compositions in a protein-stabilised oil-in-water emulsion system. The second objective investigated the preparation and characterisation of an encapsulated emulsifier system, including its physicochemical properties, stability after reconstitution and functionality in model emulsions. Five experimental studies were carried out to meet these objectives. A model emulsion prepared by microfluidisation to mimic the characteristics of a beverage emulsion was used to investigate the effect of the composition of mono- and diglycerides (unsaturation of fatty acids; monoglyceride content) and co-emulsifier (sodium stearate) content on the physical properties and stability against creaming in protein-stabilised emulsions. The experimental results demonstrated that emulsions with 0.2% MDGs produced 15-30% smaller oil droplets and 17-27% lower polydispersity indices compared to the control (no MDG). Sodium stearate (6% w/w of MDG) increased the negativity of zeta potential by 12.6-17.3 mV in emulsions containing saturated MDGs and 1.8-5.0 mV in unsaturated MDGs. Unsaturated MDGs showed better creaming stability than the control after 28 days of ageing with no improvement observed for saturated MDGs. Glycerol monooleate (GMO) demonstrated the best creaming stability among the unsaturated MDGs. The next study investigated the effect of milk protein compositions (different ratio of sodium caseinate to whey protein concentrate) on physicochemical properties, creaming stability and oxidative stability of protein-stabilised emulsions containing GMO. The experimental results showed that the emulsion with only sodium caseinate produced smaller droplets (174.7 nm), a more negative zeta potential (-50.8 mV) and a more viscous emulsion (1.89 mPa s) compared to the emulsion with only WPC (191.4 nm; 38.8 mV; 1.65 mPa s). Protein composition had no significant effect on creaming stability. Eleven volatile compounds were identified as lipid oxidation markers, and six compounds (2-pentylfuran, octanal, nonanal, 3-octen-2-one, 2,4-heptadienal, 3,5 octadien-2-one isomers) demonstrated that emulsions with mixed protein types (sodium caseinate and WPC) had better oxidative stability than emulsions with a single protein type, i.e. either caseinate or WPC alone. GMO demonstrated excellent creaming stability in protein-stabilised emulsions but was unsuitable for direct aqueous applications due to its low solubility in water. In order to use GMO as a functional ingredient in beverage emulsions, the feasibility of spray-drying to encapsulate oil-soluble MDG using appropriate wall materials to produce a stable water-dispersible powder with good reconstitution properties and extended shelf life was assessed. In addition, the effect of emulsion formulation (GMO concentration (33.6%, 47.0%); dextrose equivalent (DE) values of maltodextrin (DE 10, 18)) on emulsion properties, powder properties and oxidative stability was investigated. Results showed that all homogenised emulsions were suitable for spray-drying due to their high emulsion stability against phase separation, monomodal droplet size distributions (150-180 nm) and low viscosity (20-65 mPa s). All instantised powders exhibited good dispersibility (65-90%) in water and greater oxidative stability than bulk GMO. The instantised powder with low GMO and maltodextrin DE 10 showed both good dispersibility and low lipid oxidation, demonstrating that spray-drying can successfully produce an instantised GMO powder with a longer shelf life for food applications. The application of two selected instantised GMO powders (low GMO content with maltodextrin DE 10 or DE 18) were investigated in protein-stabilised emulsions in terms of physicochemical properties, creaming stability and oxidative stability. Model emulsions with bulk GMO, two instantised GMO powders and two controls (contain either maltodextrin DE 10 or DE 18 with no GMO) were prepared using microfluidisation. The emulsion physicochemical properties were characterised by droplet size, zeta potential, viscosity and creaming index, while the oxidative stability was assessed by the formation of volatile secondary lipid oxidation products during storage (28 days at 45 °C) using gas chromatography-mass spectrometry (GC-MS). Experimental results revealed that all three emulsions with GMO had smaller average droplet sizes (180.0 nm) and narrower size distribution (polydispersity index of 0.161) compared to the two controls (197.6 nm, 0.194). All emulsions with GMO also had greater creaming stability than the control emulsions. Principal component analysis of the volatiles revealed that storage time had the greatest influence on lipid oxidation. Three lipid oxidation markers, 3-octen-2-one, 2,4-heptadienal isomer 2 and 3,5 octadien 2-one isomer 1, showed that controls had the same oxidative stability as instantised GMO, but were more stable than bulk GMO. Therefore, GMO powders can form stable protein-stabilised emulsions with good physicochemical properties and oxidative stability. The different concentrations of bulk GMO and instantised GMO powder (low GMO with maltodextrin DE 10) was evaluated in an application of a model coffee beverage emulsion in terms of physicochemical properties, creaming stability and volatile profile at different storage time. The increasing GMO level formed fresh coffee emulsions with smaller droplet sizes and narrower size distribution that resulted in greater emulsion stability against creaming compared to the control (no GMO). However, emulsions prepared with 0.1% and 0.2% GMO were not stable at pH near to the isoelectric point of casein during storage and resulted in the growth of droplet size. These emulsions at 28 days of storage showed the presence of flocculated oil droplets due to protein aggregates when visualised using an optical microscope. The visible sediment particles in the emulsions with 0.2% GMO were associated with protein aggregate induced flocculation and could be explained by having a zeta potential below the critical level for stability ( 30 mV). The emulsions with 0.03% GMO powder demonstrated greater creaming stability than the control emulsions and had stable droplet size, zeta potential and viscosity. The chemical stability was similar to the control emulsions demonstrated by the very similar volatile concentrations. In conclusion, the results from this thesis provide new insights into the relationship between milk proteins and a MDG-based emulsifier system and their effects on emulsion properties and volatile profile in model protein-stabilised and coffee emulsions. The knowledge from this study is useful to formulate a ready-to-drink coffee beverage with the desired emulsion properties and shelf stability. This study also presents an innovative application of spray-drying to design an emulsifier system that is not only in the right format for beverage emulsions but achieves the same functionality in the products at a lower application rate. Further development may be required to determine optimum dose rates for various food and beverage applications; but the instantised GMO powder will give better control over the dosage to ensure the desired functionality is obtained

Application of a Novel Instantized Glycerol Monooleate Ingredient in a Protein-Stabilized Oil-In-Water Emulsion

Glycerol monooleate (GMO), casein and whey proteins are surfactants that can stabilize emulsion systems. This study investigates the impact of instantized GMO powders on creaming stability and oxidative stability in protein-stabilized emulsions. Model emulsions with bulk GMO, two instantized GMO powders, and two controls (without GMO) were produced by microfluidization. The droplet size, ζ-potential, viscosity, and creaming index of the emulsions were measured, while oxidative stability was evaluated by analysis of volatile compounds during storage (28 days, 45 °C) using gas chromatography mass spectrometry. Emulsions with GMO produced smaller average droplet sizes (180.0 nm) with a narrower distribution (polydispersity index of 0.161) compared to the controls (197.6 nm, 0.194). The emulsion stability of instantized emulsions was as good as bulk GMO, which were both better than controls. Based on the relative abundance of 3-octen-2-one, 2,4-heptadienal isomer 2, and 3,5-octadien-2-one isomer 1, the oxidative stability of the instantized emulsions was not significantly different from controls; however, bulk GMO emulsion showed significantly lower stability than controls. Instantized GMO powders can successfully produce physically stable protein-stabilized emulsions with good oxidative stability in a convenient powdered format

A high performance liquid chromatography method for determination of furfural in crude palm oil

A modified steam distillation method was developed to extract furfural from crude palm oil (CPO). The collected distillates were analysed using high performance liquid chromatography (HPLC) coupled with an ultraviolet diode detector at 284 nm. The HPLC method allowed identification and quantification of furfural in CPO. The unique thermal extraction of CPO whereby the fresh fruit bunches (FFB) are first subjected to steam treatment, distinguishes itself from other solvent-extracted or cold-pressed vegetable oils. The presence of furfural was also determined in the fresh palm oil from FFB (without undergoing the normal extraction process), palm olein, palm stearin, olive oil, coconut oil, sunflower oil, soya oil and corn oil. The chromatograms of the extracts were compared to that of standard furfural. Furfural was only detected in CPO. The CPO consignments obtained from four mills were shown to contain 7.54 to 20.60 mg/kg furfural

Pretreatment with a Heat-Killed Probiotic Modulates the NLRP3 Inflammasome and Attenuates Colitis-Associated Colorectal Cancer in Mice.

Colorectal cancer (CRC) is one of the most common malignancies worldwide. Inflammation contributes to cancer development and inflammatory bowel disease is an important risk factor for CRC. The aim of this study is to assess whether a widely used probiotic Enterococcus faecalis can modulate the NLRP3 inflammasome and protect against colitis and colitis-associated CRC. We studied the effect of heat-killed cells of E. faecalis on NLRP3 inflammasome activation in THP-1-derived macrophages. Pretreatment of E. faecalis or NLRP3 siRNA can inhibit NLRP3 inflammasome activation in macrophages in response to fecal content or commensal microbes, P. mirabilis or E. coli, according to the reduction of caspase-1 activation and IL-1β maturation. Mechanistically, E. faecalis attenuates the phagocytosis that is required for the full activation of the NLRP3 inflammasome. In in vivo mouse experiments, E. faecalis can ameliorate the severity of intestinal inflammation and thereby protect mice from dextran sodium sulfate (DSS)-induced colitis and the formation of CRC in wild type mice. On the other hand, E. faecalis cannot prevent DSS-induced colitis in NLRP3 knockout mice. Our findings indicate that application of the inactivated probiotic, E. faecalis, may be a useful and safe strategy for attenuation of NLRP3-mediated colitis and inflammation-associated colon carcinogenesis

Pretreatment with a Heat-Killed Probiotic Modulates the NLRP3 Inflammasome and Attenuates Colitis-Associated Colorectal Cancer in Mice

Colorectal cancer (CRC) is one of the most common malignancies worldwide. Inflammation contributes to cancer development and inflammatory bowel disease is an important risk factor for CRC. The aim of this study is to assess whether a widely used probiotic Enterococcus faecalis can modulate the NLRP3 inflammasome and protect against colitis and colitis-associated CRC. We studied the effect of heat-killed cells of E. faecalis on NLRP3 inflammasome activation in THP-1-derived macrophages. Pretreatment of E. faecalis or NLRP3 siRNA can inhibit NLRP3 inflammasome activation in macrophages in response to fecal content or commensal microbes, P. mirabilis or E. coli, according to the reduction of caspase-1 activation and IL-1β maturation. Mechanistically, E. faecalis attenuates the phagocytosis that is required for the full activation of the NLRP3 inflammasome. In in vivo mouse experiments, E. faecalis can ameliorate the severity of intestinal inflammation and thereby protect mice from dextran sodium sulfate (DSS)-induced colitis and the formation of CRC in wild type mice. On the other hand, E. faecalis cannot prevent DSS-induced colitis in NLRP3 knockout mice. Our findings indicate that application of the inactivated probiotic, E. faecalis, may be a useful and safe strategy for attenuation of NLRP3-mediated colitis and inflammation-associated colon carcinogenesis