Preparation of mango kernel fat stearin-based hard chocolate fats via physical blending and enzymatic interesterification

Effect of substrate composition on physicochemical properties of the medium-long-medium structured triacylglycerol

BACKGROUND

Nutritional and functional qualities and applications of structured lipids (SL) depend on the composition and molecular structure of fatty acids in the glycerol backbone of triacylglycerol (TAG). However, the relationship between the substrate composition and physicochemical qualities of SL has not been revealed. The investigation aims to disclose the effect of substrate composition on the physicochemical properties of medium-long-medium structured lipids (MLM-SLs) by enzymatic interesterification of Lipozyme TLIM/RMIM.

RESULTS

The medium-long-chain triacylglycerol (MLCT) yield could reach 70.32%, including 28.98% CaLCa (1,3-dioctonyl-2-linoleoyl glyceride) and 24.34% CaOCa (1,3-didecanoyl-2-oleoyl glyceride). The sn-2 unsaturated fatty acid composition mainly depended on long-chain triacylglycerol (LCT) in the substrate. The increased carbon chain length and double bond in triacylglycerol decreased its melting and crystallization temperature. The balanced substrate composition of MCT/LCT increased the size and finer crystals. Molecular docking simulation revealed that the MLCT molecule mainly interacted with the catalytic triplets of Lipozyme TLIM (Arg81-Ser83-Arg84) and the Lipozyme RMIM (Tyr183-Thr226-Arg262) by OH bond. The oxygen atom of the ester on the MLCT molecule was primarily bound to the hydrogen of hydroxyl and amino groups on the binding sites of Lipozyme TLIM/RMIM. The intermolecular interplay between MLCT and Lipozyme RMIM is more stable than Lipozyme TLIM due to the formation of lower binding affinity energy.

CONCLUSION

This research clarifies the interaction mechanism between MLCT molecules and lipases, and provides an in-depth understanding of the relationship between substrate composition, molecular structure and physicochemical property of MLM-SLs. © 2023 Society of Chemical Industry.

Enzymatic interesterification improves the lipid composition, physicochemical properties and rheological behavior of Cinnamomum camphora seed kernel oil, Pangasius bocourti stearin and perilla seed oil blends

The study aimed to investigate the effect of enzymatic interesterification on the lipid composition, physicochemical properties and rheological behavior of Cinnamomum camphora seed kernel oil (CCSKO), Pangasius bocourti stearin (PBST) and perilla seed oil (PSO) blends. The results showed that the interesterification process significantly changed the TAG profile of the blends. Lipid products from the enzymatic interesterification (EIE) had significantly lower slide melting point and solid fat content than the non-interesterification (NIE) lipid products. Interesterification process changed the crystal polymorphic forms from β > β' of NIE to β < β' of EIE. The crystal morphology of EIE was smaller and more diffuse compared to the NIE. Moreover, EIE showed improved rheological behavior, which was more suitable for food margarine preparation. The findings have provided a theoretical basis for the potential application of Lipozyme TL IM modified lipid products in the food industry.

Physical Blending of Fractionated Bambangan Kernel Fat Stearin and Palm Oil Mid-Fraction to Formulate Cocoa Butter Equivalent

In this study, the physicochemical properties, composition, thermal properties, and crystal microstructure of fractionated bambangan kernel fat stearin and palm oil mid-fraction blends were investigated with respect to a potential cocoa butter equivalent. The blends were prepared in five ratios, and all of the blends exhibited similar physicochemical properties to cocoa butter. Although all of the blends had similar physicochemical properties, the blend containing 70% bambangan kernel fat stearin and 30% palm oil mid-fraction showed remarkable similarity to cocoa butter. The blend had similar fatty acid and triacylglycerol content to cocoa butter with 18.74% palmitic acids, 38.26% stearic acids, 34.05% oleic acids, 15.20% 1,3-dipalmitoyl-2-oleoyl glycerol, and 29.74% 1,3-disteroyl-2-oleoyl glycerol with improved thermostability (high solid fat content at 30 °C but reaching 0% at 40 °C). It also exhibited spherulite crystals with a needle-like crystal structure of 50 µm. This mixture showed good compatibility with cocoa butter at all mixing ratios; hence, it is suggested as a potential cocoa butter equivalent.

Effect of palm stearin on the physicochemical characterization and capsaicinoid digestion of Sichuan hotpot oil

Beef tallow (BT) is the common hotpot oil used in Sichuan hotpot, increasing its characteristic flavors and making it taste better. However, the cholesterol content in BT is high, which may induce cardiovascular diseases. In this study, the effect of palm stearin (PS) on Sichuan hotpot oil was evaluated. The PS: BT blends showed similar physicochemical properties to BT from the results of sensory evaluation, pulsed NMR, DSC, and polar light micrograph (PLM). Furthermore, since spiciness is the essential characteristic of Sichuan hotpot, the digestive properties of capsaicinoids in hotpot oil were used as an evaluation index. The results showed that the digestive properties of capsaicinoids in hotpot oil containing PS were consistent with those without PS. In conclusion, PS can be partially used to replace BT, which can broaden the types of oil used for hotpot and help develop a new hotpot oil.

Effect of solvent pre-treatment on the physicochemical, thermal profiles and morphological behavior of Mangifera pajang seed fat

In this work, the effect of solvent pre-treatment (hexane, petroleum ether and ethanol) on the physicochemical, thermal and morphology behavior of Mangifera pajang seed fat (MPSF) were investigated. Fat extraction was performed using Soxhlet method, and results showed that the yield, physicochemical, and crystalline structures of the MPSF were significantly (p < 0.05) influenced by the extraction solvents. Hexane gave the highest fat yield (7.67 %) with low unsaturation value (52.13 g iodine/g) compared with petroleum ether and ethanol. Hexane MPSF also had low oxidation rate (peroxide value of 1.1 mEq/g). Both non-stabilized and stabilized hexane MPSF showed a single melting endothermic peak at high temperature with onset, maximum peak and offset temperature of 16.23 ˚C-18.21 °C, 28.22 ˚C-31.25 °C and 34.85 ˚C-39.58 °C, respectively. Hexane MPSF crystallized rapidly at high temperature with single maximum peak starting at 16.51 ˚C-16.68 °C and ending at 0.23 ˚C-1.13 °C. In comparison with ethanol extract, hexane MPSF demonstrated a compact crystalline structure with a large densely packed center. Therefore, MPSF obtained from hexane presented better overall quality than those obtained from other extraction solvents. MPSF exhibited similar melting and morphological behavior to mango kernel fat and commercial cocoa butter. These results suggested that hexane was the best solvent for the extraction of MPSF. This fat also has the potential to be applied as a cocoa butter alternative fat or functional fat.

Enzymatic Interesterification of Palm Stearin and Palm Olein Blend Catalyzed by sn-1,3-Specific Lipase: Interesterification Degree, Acyl Migration, and Physical Properties

Acyl migration of fatty acid at sn-2 is often observed alongside enzymatic interesterification (EIE), causing the loss of lipase selectivity toward the acyl group at sn-1,3. In this study, an oil blend consisting of palm stearin (PST) and palm olein (POL) was interesterified via a chemical interesterification (CIE) and enzymatic method using a packed bed reactor. Characterization in terms of the triacylglycerol (TAG) compositions, sn-2 fatty acid distributions, and solid fat content profiles was performed. In comparison to that of CIE fats, EIE fats showed different modification effects on the solid fat content. Under similar reaction conditions, different interesterification degrees (IDs) were obtained according to the various blend ratios. Using the same mass ratio of substrates (POL/PST of 9:1), the EIE reaction time and temperature affected the ID and the change in the fatty acyl group at the sn-2 position. Under the reaction time of 46 min, an ID of 94.41% was acquired, while at 80 °C, the degree of acyl migration at sn-2 was 92.87%. EIE with high acyl migration exhibited a lower crystallization rate than that of EIE with low acyl migration. However, the effect of acyl migration on crystal polymorphism and oxidative stability was insignificant. Outcomes from this study are meaningful for the establishment of a theoretical basis for a controlled positional-specific EIE that is catalyzed by sn-1,3-specific lipase.

Heat resistant chocolate development for subtropical and tropical climates: a review

Heat resistant chocolate (HRC) which can retain the desired texture and mouthfeel in tropical and subtropical climatic conditions has become a major research area in the chocolate industry. Liking of the chocolate products keeps on changing with the geographical conditions of the world due to the availability of ingredients from local resources and consumer's taste preferences. The geographical changes also bring about the change in climatic conditions and as such no chocolates have been formulated to withstand the hot tropical or sub-tropical temperature conditions. Textural issues and various storage related problems faced due to meltability of chocolate in different countries has opened up a broad research field of sustainable HRC manufacturing. Over the years, there are broadly three different approaches (fat modification, sugar structure modification and innovative process approach) to develop the HRC and all these scientific approaches have given different scientific insights about improving the heat resistance characteristics and textural stability of chocolate. There is a lack or coordinated fundamental and applied research related to cocoa butter polymorphism, and thermal-textural issues during product development/storage. This review paper is an attempt to describe the different scientific approaches for developing HRC and how they affect the physical/sensory chocolate attributes.

Effect of sorbitan monopalmitate on the polymorphic transitions and physicochemical properties of mango butter

The present study reports the effect of sorbitan monopalmitate (SM) as a crystallization modifier on the physicochemical properties of mango butter (MB). The concentration of SM was varied in the range of 1 and 5 wt%. The addition of SM promoted the aggregation of globular MB crystals. The FTIR patterns did not show any significant changes when SM was added. XRD and DSC analyses confirmed the crystallization of MB crystals in stable β' and β (V) polymorphic states. However, SM also introduced imperfections in the crystal lattices of MB. Among all formulations, M2 (SM; 1% w/w) possessed a mechanically stable network structure. The crystallization rate of MB was tailored by SM in a concentration-dependent manner. The solid content was highest in M4 (SM; 5% w/w) at 10 °C and 30 °C among all the oleogels. In gist, SM in manageable quantities can be utilized for preparing custom-tailored MB-based products.

Rhizomucor miehei lipase-catalysed synthesis of cocoa butter equivalent from palm mid-fraction and stearic acid: Characteristics and feasibility as cocoa butter alternative

In this study, cocoa butter equivalents (CBEs) were prepared through enzymatic interesterification of palm mid-fraction (PMF) with stearic acid (SA). The reaction process parameters were experimented and the performance of the product was analysed. PMF and stearic acid (at a mass ratio of 1:2) were catalysed by 80 g kg^-1 enzyme loading of Lipozyme RM IM fromRhizomucor mieheiat 60 °C for 120 min. The yield of the CBE product was more than 92%, and the CBE resembled cocoa butter (CB) in terms of its triacylglycerol composition. The hardness of the CBE product was higher than that of CB at different storage temperatures, but this difference was not obvious at 25 °C. The polymorphic structures and SFC curve of the CBE were similar to those of the CB. In addition, the CBE could be mixed with CB in any ratio without an obvious eutectic phenomena. Up to 40% CBE could be added to CB without significantly affecting the thermodynamic properties of CB. Thus, replacing CB with the CBE product is feasible.

Formation and properties of dark chocolate prepared using fat mixtures of cocoa butter and symmetric/asymmetric stearic-oleic mixed-acid triacylglycerols: Impact of molecular compound crystals

This paper reports an experimental study of the formation and properties of dark chocolate prepared using novel CB alternative fats (CBAs): symmetric (OS_atO) and asymmetric (S_atS_atO) mixed-acid triacylglycerols (TAGs), in which Sat and O represent saturated fatty acids (stearic:S + palmitic:P) and oleic acid moieties, respectively. It was found that the ternary fat mixtures of CB/S_atS_atO/OS_atO with a ratio of CB/(S_atS_atO + OS_atO) of 1:1 formed the most stable β-form of the double chain length (DCL) structure (β-2), which revealed sufficient hardness and sharp melting profiles around body temperature without tempering processes. Fat bloom formation was not observed in dark chocolate with CBAs at ratios of CB/S_atS_atO/OS_atO of 50/20/30-50/0/50 during the one-year storage test at temperatures between 15 °C and 30 °C. Overall, the present study has shown that fat mixtures made of CB/S_atS_atO/OS_atO, which are rich in oleic acid moieties, can be employed as a cocoa butter equivalent (CBE) fat without tempering procedures.

Evaluation of enzymatic interesterification in structured triacylglycerols preparation: a concise review and prospect

Enzymatic interesterification (EIE) is one of the emerging technologies in the specialty fats industry. EIE has several advantages over the conventional chemical interesterification method, such that the process has higher flexibility and efficiency, is environmentally friendly and the immobilized enzyme can be recycled besides of the lower requirement for substrate's acid value. The physical properties and nutritional qualities of the fats and oils are modified after EIE, depending on the change in the position of fatty acids on the triacylglycerol (TAG) molecules. Evaluation of the interesterification reaction are important and useful in terms of its technological applications. This paper summarizes the conventional methods and the advancement for evaluating EIE processes, e.g., determination of the change in slip melting points, solid fat contents, TAG with equivalent carbon numbers, and sn-2 fatty acid compositions of the end product. Nonetheless, these methods are not comprehensive because during the EIE process, acyl migration occurs. A novel and convenient evaluation model which is based on the fatty acid distribution on the glycerol-backbone is proposed as a perspective. This model can be employed to monitor the interesterification degree and acyl migration during a regiospecific EIE process, which serves as a reaction rule that can be employed to control and optimize the EIE process, thereby producing structured TAG with desired properties.

Effect of polyglycerol polyricinoleate on the polymorphic transitions and physicochemical properties of mango butter

Emulsifiers act as Fat crystal modifiers and can modulate the crystallization process of fats. In this study, we have reported the effect of polyglycerol polyricinoleate (PGPR) on the physicochemical properties of an underutilized vegetable fat "mango butter" (MB). MB-PGPR based formulations were prepared by heat-cool method. Microscopic studies showed that PGPR resulted in the formation of globular MB crystals. XRD and thermal studies conjointly suggested that the MB crystals were predominantly crystallized as β-polymorph. However, PGPR induced imperfections within the MB crystals. FTIR spectroscopy revealed that PGPR considerably varied the local environment of the MB crystals. PGPR also altered the nucleation time and crystallization rate of the MB crystal formation. The MB formulation that contained 2.5% (w/w) PGPR was found to have good mechanical stability. In gist, the addition of PGPR (as a crystal modifier) can help us to influence the crystal behavior and physicochemical properties of the MB fat.

Characterization of enzymatically interesterified palm oil-based fats and its potential application as cocoa butter substitute

Cocoa butter substitutes (CBS) used for chocolate preparation was produced using a mixture of palm kernel oil (PKO) and enzymatically interesterified fats. The interesterified fats consisted of palm olein (POL), fully hydrogenated palm oil (FHPO) and PKO that were catalyzed using Lipozyme TL IM at 65 °C in a solvent-free packed bed reactor. An interesterification degree of 97.10% was obtained using feed flow rate of 70 mL/min and the interesterified fats showed steep solid fat content (SFC) curve characteristics with low SFC at high temperature. In the binary system, PKO and the interesterified fats showed good compatibility at 5-10 °C, while eutectic effects were observed at 15-35 °C. CBS produced from PKO and the interesterified fats in a mass ratio of 4:6 (CBS-46) and 3:7 (CBS-37) had crystals formed prominently in the β' form. Without the need of a tempering process, chocolate made using CBS-46 as the base oil exhibited the desired properties in terms of hardness and fracturability.