Interesterified fats: What are they and why are they used? A briefing report from the Roundtable on Interesterified Fats in Foods

Abridgement of Microbial Esterases and Their Eminent Industrial Endeavors

Esterases are hydrolases that contribute to the hydrolysis of ester bonds into both water-soluble acyl esters and emulsified glycerol-esters containing short-chain acyl groups. They have garnered significant attention from biotechnologists and organic chemists due to their immense commercial value. Esterases, with their diverse and significant properties, have become highly sought after for various industrial applications. Synthesized ubiquitously by a wide range of living organisms, including animals, plants, and microorganisms, these enzymes have found microbial esterases to be the preferred choice in industrial settings. The cost-effective production of microbial esterases ensures higher yields, unaffected by seasonal variations. Their applications span diverse sectors, such as food manufacturing, leather tanneries, paper and pulp production, textiles, detergents, cosmetics, pharmaceuticals, biodiesel synthesis, bioremediation, and waste treatment. As the global trend shifts toward eco-friendly and sustainable practices, industrial processes are evolving with reduced waste generation, lower energy consumption, and the utilization of biocatalysts derived from renewable and unconventional raw materials. This review explores the background, structural characteristics, thermostability, and multifaceted roles of bacterial esterases in crucial industries, aiming to optimize and analyze their properties for continued successful utilization in diverse industrial processes. Additionally, recent advancements in esterase research are overviewed, showcasing novel techniques, innovations, and promising areas for further exploration.

Postprandial lipid and vascular responses following consumption of a commercially-relevant interesterified palmitic acid-rich spread in comparison to functionally-equivalent non-interesterified spread and spreadable butter: a randomised controlled trial in healthy adults

Background: Interesterification is an industrial processing technique used widely where hard fats are essential for functionality and consumer acceptability, e.g. margarines and lower fat spreads. Objective: The aim of this study was to compare acute cardiovascular effects of functionally equivalent spreads (similar solid fat content) made with interesterified (IE) or non-IE palm-based fats, or spreadable butter. Methods: A randomised, controlled, 4-armed crossover, double-blind study (25 men, 25 women; 35-75 years; healthy; mean BMI 24.5, SD 3.8), compared effects of mixed nutrient meals containing 50 g fat from functionally equivalent products [IE spread, non-IE spread and spreadable butter (SB), with rapeseed oil (RO) as a reference treatment: with 16.7%, 27.9%, 19.3% and 4% palmitic acid, respectively] on 8 h postprandial changes in plasma triacylglycerol (TAG) and endothelial dysfunction (flow-mediated dilatation; FMD). Circulating reactive oxygen species (estimated using a neutrophil oxidative burst assay), glucose, insulin, NEFA, lipoprotein particle profiles, inflammatory markers (glycoprotein acetylation (Glyc-A) and IL-6), and biomarkers of endotoxemia were measured. Results: Postprandial plasma TAG concentrations after test meals were similar. However following RO versus the 3 spreads, there were significantly higher postprandial apolipoprotein B concentrations, and small HDL and LDL particle concentrations, and lower postprandial extra-large, large, and medium HDL particle concentrations, as well as smaller average HDL and LDL particle sizes. There were no differences following IE compared to the other spreads. Postprandial FMD% did not decrease after high-fat test meals, and there were no differences between treatments. Postprandial serum IL-6 increased similarly after test meals, but RO provoked a greater increase in postprandial concentrations of glycoprotein acetyls (GlycA), as well as 8 h sCD14, an endotoxemia marker. All other postprandial outcomes were not different between treatments. Conclusions: In healthy adults, a commercially-available IE-based spread did not evoke a different postprandial triacylglycerol, lipoprotein subclass, oxidative stress, inflammatory or endotoxemic response to functionally-equivalent, but compositionally-distinct alternative spreads. Clinical trial registry number: NCT03438084 (https://ClinicalTrials.gov).

Interesterified palm oil promotes insulin resistance and altered insulin secretion and signaling in Swiss mice

Interesterified fats have been used to replace trans-fat in ultra-processed foods. However, their metabolic effects are not completely understood. Hence, this study aimed to investigate the effects related to glucose homeostasis in response to interesterified palm oil or refined palm oil intake. Four-week-old male Swiss mice were randomly divided into four experimental groups and fed the following diets for 8 weeks: a normocaloric and normolipidic diet containing refined palm oil (PO group) or interesterified palm oil (IPO group); a hypercaloric and high-fat diet containing refined PO (POHF group) or interesterified PO (IPOHF group). Metabolic parameters related to body mass, adiposity and food consumption showed no significant differences. As for glucose homeostasis parameters, interesterified palm oil diets (IPO and IPOHF) resulted in higher glucose intolerance than unmodified palm oil diets (PO and POHF). Euglycemic-hyperinsulinemic clamp assessment showed a higher endogenous glucose production in the IPO group compared with the PO group. Moreover, the IPO group showed significantly lower p-AKT protein content (in the muscle and liver tissues) when compared with the PO group. Analysis of glucose-stimulated static insulin secretion (11.1 mmol/L glucose) in isolated pancreatic islets showed a higher insulin secretion in animals fed interesterified fat diets (IPO and IPOHF) than in those fed with palm oil (PO and POHF). Interesterified palm oil, including in normolipidic diets, can impair insulin signaling in peripheral tissues and increase insulin secretion by β-cells, characterizing insulin resistance in mice.

Safety evaluation of the food enzyme triacylglycerol lipase from the genetically modified Aspergillus luchuensis strain FL105SC

The food enzyme triacylglycerol lipase (triacylglycerol acylhydrolase; EC 3.1.1.3) is produced with the genetically modified Aspergillus luchuensis strain FL105SC by Advanced Enzyme Technologies Ltd. The genetic modifications do not give rise to safety concerns. The food enzyme is free from viable cells of the production organism and its DNA. It is intended to be used in an immobilised form for the production of modified fats and oils by interesterification. Genotoxicity tests did not indicate a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level (NOAEL) of 783 mg TOS/kg body weight per day. As the food enzyme is used in an immobilised form and as any residual amounts of the food enzyme-total organic solids (TOS) are removed during the food manufacturing process, dietary exposure was not calculated. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that a risk of allergic reactions upon dietary exposure cannot be excluded, but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Safety evaluation of the food enzyme triacylglycerol lipase from the genetically modified Aspergillus luchuensis strain FL108SC

The food enzyme triacylglycerol lipase (triacylglycerol acylhydrolase; EC 3.1.1.3) is produced with the genetically modified Aspergillus luchuensis strain FL108SC by Advanced Enzyme Technologies Ltd. The genetic modifications do not give rise to safety concerns. The food enzyme is free from viable cells of the production organism and its DNA. It is intended to be used in an immobilised form for the production of modified fats and oils by interesterification. Genotoxicity tests did not raise safety concerns. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rodents. The Panel identified a no observed adverse effect level (NOAEL) at the highest dose of 774 mg TOS/kg body weight per day. As the food enzyme is used in an immobilised form and as any residual amounts of the food enzyme-total organic solids (TOS) are removed during the food manufacturing process, dietary exposure was not calculated. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that a risk of allergic reactions upon dietary exposure cannot be excluded, but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Oleogels as a Fat Substitute in Food: A Current Review

Fats and oils in food give them flavor and texture while promoting satiety. Despite the recommendation to consume predominantly unsaturated lipid sources, its liquid behavior at room temperature makes many industrial applications impossible. Oleogel is a relatively new technology applied as a total or partial replacement for conventional fats directly related to cardiovascular diseases (CVD) and inflammatory processes. Some of the complications in developing oleogels for the food industry are finding structuring agents Generally Recognized as Safe (GRAS), viable economically, and that do not compromise the oleogel palatability; thus, many studies have shown the different possibilities of applications of oleogel in food products. This review presents applied oleogels in foods and recent proposals to circumvent some disadvantages, as reaching consumer demand for healthier products using an easy-to-use and low-cost material can be intriguing for the food industry.

Cleaner lipid processing: Supercritical carbon dioxide (Sc-CO2) and short path distillation

Today, regulations and consumer awareness demand production technologies with minimum impact on the environment and maximum utilization of available resources. In the field of lipids, two well-known technologies for avoiding the use of organic solvents and chemicals stand out: supercritical (Sc) fluids and short path distillation (SPD). To date, both technologies involve high operating costs that have limited their application to selected high value-added products which are high temperature sensitive. However, improvements in process control and materials make further implementation of these techniques possible. In this chapter, an integrative review has been carried out with the aim of compiling the literature on the application of these technologies to lipid extraction, micronization and fractionation of liquid mixtures. Special attention has been paid to the separation of compounds by both technologies: deacidification, partial purification of acylglycerol compounds, isolation of unsaponifiable compounds and separation of toxic and polluting compounds.

Trans-fat labelling information on prepackaged foods and beverages sold in Hong Kong in 2019

OBJECTIVE

To examine the labelling status of trans-fat of pre-packaged foods sold in Hong Kong.

DESIGN

Data from 19 027 items in the 2019 FoodSwitch Hong Kong database were used. Ingredient lists were screened to identify specific (e.g. partially hydrogenated vegetable oil, PHVO) and non-specific trans-fat ingredient indicators (e.g. hydrogenated oil). Trans-fat content was obtained from the on-pack nutrition labels, which was converted into proportion of total fat (%total fat). Descriptive statistics were calculated for trans-fat content and the number of specific, non-specific and total trans-fat ingredients indicators found on the ingredients lists. Comparisons were made between regions using one-way ANOVA and χ2 for continuous and categorical variables, respectively.

SETTING

Cross-sectional audit.

PARTICIPANTS

Not applicable.

RESULTS

A total of 729 items (3·8 % of all products) reported to contain industrially produced trans-fat, with a median of 0·4 g/100 g or 100 ml (interquartile range (IQR): 0·1-0·6) and 1·2 %totalfat (IQR: 0·6-2·9). 'Bread and bakery products' had the highest proportion of items with industrially produced trans-fat (18·9 %). 'Non-alcoholic beverages' had the highest proportion of products of 'false negatives' labelling (e.g. labelled as 0 trans-fat but contains PHVO; 59·3 %). The majority of products with trans-fat indicator originated from Asia (70 %).

CONCLUSIONS

According to the labelling ∼4 % of pre-packaged food and beverages sold in Hong Kong in 2019 contained industrially produced trans-fat, and a third of these had trans-fat >2 %total fat. The ambiguous trans-fat labelling in Hong Kong may not effectively assist consumers in identifying products free from industrially produced trans-fat.

How Arrestins and GRKs Regulate the Function of Long Chain Fatty Acid Receptors

FFA1 and FFA4, two G protein-coupled receptors that are activated by long chain fatty acids, play crucial roles in mediating many biological functions in the body. As a result, these fatty acid receptors have gained considerable attention due to their potential to be targeted for the treatment of type-2 diabetes. However, the relative contribution of canonical G protein-mediated signalling versus the effects of agonist-induced phosphorylation and interactions with β-arrestins have yet to be fully defined. Recently, several reports have highlighted the ability of β-arrestins and GRKs to interact with and modulate different functions of both FFA1 and FFA4, suggesting that it is indeed important to consider these interactions when studying the roles of FFA1 and FFA4 in both normal physiology and in different disease settings. Here, we discuss what is currently known and show the importance of understanding fully how β-arrestins and GRKs regulate the function of long chain fatty acid receptors.

INTERESTERIFIED FAT MATERNAL CONSUMPTION BEFORE CONCEPTION PROGRAMMS MEMORY AND LEARNING OF ADULTHOOD OFFSPRING: how big is this deleterious repercussion?

In recent years, interesterified fat (IF) has largely replaced trans fat in industrialized food. Studies of our research group showed that IF consumption may not be safe for central nervous system (CNS) functions. Our current aim was to evaluate IF maternal consumption before conception on cognitive performance of adult rat offspring. Female Wistar rats were fed with standard chow plus 20% soybean and fish oil mix (control group) or plus 20% IF from weaning until adulthood (before mating), when the diets were replaced by standard chow only. Following the gestation and pups' development, locomotion and memory performance followed by neurotrophin immunocontent and fatty acids (FA) profile in the hippocampus of the adulthood male offspring were quantified. Maternal IF consumption before conception decreased hippocampal palmitoleic acid incorporation, proBDNF and BDNF levels, decreasing both exploratory activity and memory performance in adult offspring. Considering that, the adult male offspring did not consume IF directly, further studies are needed to understand the molecular mechanisms and if the IF maternal preconception consumption could induce the epigenetic changes observed here. Our outcomes reinforce an immediate necessity to monitor and / or question the replacement of trans fat by IF with further studies involving CNS functions.

The Influence of Interesterification on the Thermal and Technological Properties of Milkfat-Rapeseed Oil Mixture and Its Potential Use in Incorporation of Model Meat Batters

Enzymatic interesterification gives the possibility to obtain a wide range of lipids with a modified structure. In the present study, model meat batters were produced from chicken breast muscles and enzymatically interesterified fats: milkfat:rapeseed oil (3:2 w/w). Fatty acids composition and their positional distribution in triacylglycerol, melting profile and oxidative stability have been determined in fats used for interesterification, after interesterification and extracted from meat batters. In meat batters, the physiochemical parameters were determined. Interesterified fats were characterized by significantly lower induction times than noninteresterified fat (85.29 and 18.21 min, respectively). Meat batters were also characterized by a lower oxidative stability of lipid fraction (24.90 and 13.67 min) than lipids used to their production. A higher content of unsaturated fatty acids was found in meat batters with noninteresterified and interesterified fats (69.40% and 70.03%, respectively) than in the control meat batter with a pork jowl (58.63%). In comparison to the control product, meat batter prepared with interesterified mixture was characterized by significantly lower apparent viscosity. In the analyzed meat batters, there were no differences in thermal drip and penetration force. The incorporation of interesterified milkfat with rapeseed oil in model meat batters can be a strategy to improve the nutritional quality without adversely affecting the quality characteristics.

Interesterified palm oil impairs glucose homeostasis and induces deleterious effects in liver of Swiss mice

BACKGROUND

Interesterified fats have largely replaced the partially hydrogenated oils which are the main dietary source of trans fat in industrialized food. This process promotes a random rearrangement of the native fatty acids and the results are different triacylglycerol (TAG) molecules without generating trans isomers. The role of interesterified fats in metabolism remains unclear. We evaluated metabolic parameters, glucose homeostasis and inflammatory markers in mice fed with normocaloric and normolipidic diets or hypercaloric and high-fat diet enriched with interesterified palm oil.

METHODS

Male Swiss mice were randomly divided into four experimental groups and submitted to either normolipidic palm oil diet (PO), normolipidic interesterified palm oil diet (IPO), palm oil high-fat diet (POHF) or interesterified palm oil high-fat diet (IPOHF) during an 8 weeks period.

RESULTS

When compared to the PO group, IPO group presented higher body mass, hyperglycemia, impaired glucose tolerance, evidence of insulin resistance and greater production of glucose in basal state during pyruvate in situ assay. We also observed higher protein content of hepatic PEPCK and increased cytokine mRNA expression in the IPO group when compared to PO. Interestingly, IPO group showed similar parameters to POHF and IPOHF groups.

CONCLUSION

The results indicate that substitution of palm oil for interesterified palm oil even on normocaloric and normolipidic diet could negatively modulate metabolic parameters and glucose homeostasis as well as cytokine gene expression in the liver and white adipose tissue. This data support concerns about the effects of interesterified fats on health and could promote further discussions about the safety of the utilization of this unnatural fat by food industry.