Striped mullet (Mugil cephalus) roe is used for the production of traditional delicacies in Greece (avgotaracho), Japan (karasumi) and Italy (botargo). In Greece avgotaracho is a Protected Designation of Origin product and its special taste combined with its high nutritional value of this rich in polyunsaturated fatty acids (PUFA) and bioactive compounds delicacy attracts many consumers. During the production of avgotaracho and the similar products some of the egg sacs (skeins) either break or have an inappropriate size (too small) and they can not be used for avgotaracho production. On the other hand the nutritional quality of the eggs in the broken or smaller skein is by no means inferior comparing to the rest. Proper valorization of the mullet roe by-products could lead to high nutrition value products. This work focuses on examining the potential valorization of these high nutritional value by-products for producing mullet roe oil. Three different extraction methods with potential of scale-up are examined. Namely pressure, supercritical extraction, solvent extraction are examined where mild temperature conditions and (wherever applicable) food-grade solvents are used. The oil yield, the composition of oils in fatty acids by GC-FID, the level of oil oxidation (peroxide value, p-anisidine value, K232 K268, TOTOX) and antioxidant activity (DPPH, ABTS) are determined. The potential of the above extraction methods for the production of mullet roe oil in terms of yield and oil quality is discussed.
Virgin olive oils (VOO) obtained from olives grown in different regions of our country, under changing climatic conditions, show different sensory and chemical properties. Due to the fact that primary production is affected by climatic and agricultural conditions and VOOs are supplied to the market by only physical processing. In order to determine whether these deviations are due to climatic conditions, VOOs were obtained from the olive samples collected from 39 orchards in four Region where VOO production is intense in Turkey. Analyzes were carried out regarding the quality and purity criteria of the VOOs. Samples were collected in 2017/18-2020/21 harvest years (-2 on-2 off). The maturity index (MI) values of olives and free fatty acidity (FFA), fatty acid ethyl esters (FAEE), delta-7-stigmastenol values of olive oils ranged between 0.94-4.15 and 0.07-1.27 (in oleic acid %), 1.56-27.32 mg/kg, 0.16-1.14%, respectively. Delta-7-stigmastenol values in 21 samples were outside the limit specified in the legislation (0.50-1.14%). The Fatty acid methyl esters (FAME) and FAEE of all olive oil samples were within the specified limits. In the study, multiple regression analysis was performed to investigate whether there is a relationship between climate data and delta-7-stigmastenol values by years. According to this result, it has been determined that the delta-7-stigmastenol value is high when the annual average relative humidity is low and the annual average temperature is high. There is an urgent need to make forward-looking plans due to climate change.
Several blends of palm olein (POo), super olein (SOo) and palm stearin (PS) with sunflower (SFO), soybean (SBO), rice bran (RBO), mustard (MO), olive (OO) and sesame (SMO) oils were prepared in different ratios to obtain improved blends with desired fatty acid profile and physicochemical properties as an alternate to PHO trans-free oils/fats. Among the prepared edible oil blends, the 6:4 (w/w) blends of POo/SOo with SFO and SBO, 2:8 (w/w) POo:RBO and 1:1 (w/w) blend of SOo:SMO, 1:1 /4:6 (w/w) blends of PS with RBO and SMO were found to have balanced FA profiles closer to AHA/JMHW/WHO recommended SFA:MUFA:PUFA ratios of 1:1:1/1:1.5:1/1:1.5:0.7 and also desired physico-chemical properties. These blends were further processed for enzymatic interesterification (IE) employing Lipozyme TLIM in a specially designed bioreactor to obtain trans-free IE structured lipids (SLs) for potential use in cooking and trans-free fat formulation applications. In addition, the developed palm-based edible oil blends and the respective IE products can help the stake holders in replacing PHO/vanaspati, which in turn can play a significant role in implementing the FSSAI regulation of reducing the trans fats to 2% in the country by 2022.
Oleogels and emulgels were developed with winterized algal oil from Schizochytrium spp. rich in ω-3 fatty acids (FAs) to overcome physical limitations of using a highly unsaturated lipid source in food applications. Both gel types were developed using monolaurin or a combination of mono- and diacylglycerols (MAG/DAG) as the gelator at concentrations of 8, 10, or 12%, w/w, in oil or emulsion. A 14-day accelerated oxidation study was conducted using peroxide value, p-Anisidine value, and change in FA composition to measure the level of oxidation. Oleogel and emulgel samples exhibited a higher oxidative stability than bulk algal oil and oil-in-water emulsion as control groups, respectively. The 12% monolaurin oleogel outperformed others in oxidative stability, preventing oxidation of approximately 17.96% and 20.43% of EPA and DHA, respectively, compared to algal oil. Physical characteristics including thermal behavior, solid fat content (SFC), rheology, morphology, and polymorphism were studied. Results indicated that MAG/DAG oleogels and monolaurin emulgels were the most physically stable. The SFC of 12% MAG/DAG oleogel at 30 °C was 10.27% whereas 12% monolaurin oleogel was only 4.51%. Both gel types developed with monolaurin and MAG/DAG could be used for different applications as they exhibited desirable qualities such as oxidative stability and improved physical characteristics.
Bigels, are prepared by homogenization of an organogel and hydrogel. Bigels can offer improved properties when compared to other gelled systems due to its semi-solid internal phase and supramolecular interactions between components. The objective of this study was to determine the effect of mono-diglycerides (MDG) on the supramolecular structure and interactions, physical stability and mechanical properties of a rice bran wax (RBW)–gelatin bigels. The organogel-to-hydrogel (OG:HG) ratios tested were 60:40, 70:30 and 80:20 with MDG incorporated at four concentrations (0.5, 1, 2, 3% (w/w)). Bigels were analyzed using nuclear magnetic resonance spectroscopy (NMR), confocal scanning laser microscopy (CSLM), Fourier transform infrared spectroscopy (FTIR), texture analysis and liquid binding capacity studies. The results showed that MDG have a dual effect on the structural organization and stability of the systems; they act as emulsifiers and/or crystallization modifiers. CSLM and FTIR showed that the addition of MDG had the greatest effect on the microstructure of the 60:40 OG:HG ratio, where MDG concentrations 0.5 and 1% (w/w) exhibited a reduction in the size of the oleogel regions while concentrations 2 and 3% (w/w) showed a phase inversion. MDG addition resulted in a gradual decrease in bigel hardness, but an enhancement of physical stability.
Oleogelation offers the possibility to reduce the saturated fatty acid (SAFA) content while maintaining the desired organoleptic properties. Hereby, SAFA are replaced by other structurants which can create a three-dimensional network that immobilizes the liquid oil. Depending on the type of structurants, different structuring routes are identified. The use of monoglycerides (MAGs) as structurants is a promising approach thanks to their great self-assembling properties. However, implementation into the food industry is still hampered due to insufficient characterization. This research includes a multiscale analysis of two dynamically produced MAG-based oleogels as a function of the storage time (up to 8 weeks). Slight differences in the production process resulted in differences in techno-functional properties between the MAG-based oleogels MO1 and MO2. MO1 consisted of larger crystals, which resulted in a lower rigidity, lower stability and lower oil binding capacity compared to the other oleogel (MO2). On the nanoscale, it was found that the crystal nanoplatelets (CNPs) of MO1 contained a higher number of lamellae compared to the MO2. Additionally, the results obtained with ultra-small angle X-ray scattering indicated a larger equivalent diameter for the CNPs of MO1. As a function of the storage time, both oleogels did not show major structural changes up to 8 weeks of storage.
Fortification of Asian sea bass bone bio-calcium (ASBC) at different levels (0-10%) into mayonnaise was carried out. Firmness, consistency and cohesiveness of mayonnaise were augmented with increasing ASBC levels (P<0.05). ASBC raised lightness (L*) and total color difference (E*), but decreased a* and b*-values of mayonnaise in a dose dependent manner (P<0.05). Higher G’, G”, viscosity and shear stress value were observed in mayonnaise sample added with ASBC. However, lower acceptability was attained when mayonnaise was added with ASBC at level higher than 2.5% due to fishy odor and grittiness perceived by panelists. Ultrasonicated ASBC (U-ASBC) was prepared using pulse mode at 70% amplitude for different times (5, 10 and 15 min) in the presence of hexane. Based on acceptability, mayonnaise added with U-ASBC using ultrasonication time of 15 min was selected. Reduced particle size with lowered volatile compounds was attained in U-ASBC powder than that of ASBC. Mayonnaise added with 7.5% U-ASBC (M-UBC-7.5) had higher viscosity with lower creaming and thermal creaming index (P<0.05) compared to the control and that added with 2.5% ASBC (M-BC-2.5). Optical microscopic images showed that denser and smaller droplet size was observed for M-BC-2.5 and M-UBC-7.5 than control. The lowest moisture, fat and carbohydrate contents were attained for M-UBC-7.5 with the higher protein, ash and calcium content (P<0.05), compared to control and M-BC-2.5. Fortification of mayonnaise with ASBC at 2.5% or U-ASBC at 7.5% could increase calcium content by 54 or 174 times, respectively, without any sensorial changes.
Protein from camelina seed is a valuable co-product that can be derived from the meal remaining after oil extraction. The current study describes the types and physicochemical properties of the major proteins present in camelina meal. Seed coat mucilage, which interferes with protein extraction, was removed from whole seeds by digestion with Viscozyme® and lipids were removed with hexane to obtain demucilaged/defatted meal. Protein comprised 51.3% of meal dry matter and the eight essential amino acids comprised 40.8% of total amino acids. The meal polypeptide profile showed bands originating from cruciferin (~44.1 and 51.7 kDa), napin (~14 kDa) and oil body proteins (OBP; ~15-20 kDa) resembling that of other crucifers. Cruciferins (11 isoforms) were the predominant proteins, while vicilins (6 isoforms) also were identified among the proteins soluble at pH 8.5. Among the proteins soluble at pH 3, napins (5 isoforms) comprised the majority, though late embryogenesis abundant proteins also were found. Camelina cruciferin and napin were confirmed to possess predominantly β-sheet and α-helix secondary structures, respectively. Camelina cruciferin structure was highly sensitive to changes in medium pH and underwent acid-induced denaturation at pH 3, but exhibited high thermal stability (>80°C) at neutral and alkaline pHs. The structure of camelina napins was less sensitive to pH. The major proteins associated with oil bodies were oleosins (6 isoforms). Identification and characterization of the properties of camelina meal proteins will enable strategic paths for co-product valorization.
Oleogelation is an efficient way to structure oil and reduce saturated fatty acids of lipid products. Multi-component gels are of particularly interest attributed to the ability to tune gel properties by alteration of the component proportions. In this study, monoacylglycerol (MAG) and diacylglycerol (DAG) are used as gelator mixture and the influence of the ratio of these two crystalline particles on the characteristics of oleogels was investigated. The crystallization and melting behavior, solid fat content (SFC), crystal morphology, polymorphism and mechanical properties of the oleogels were characterized. The oleogels with higher gelator level displayed higher oil binding ability and shorter crystal formation time. The oleogels with higher MAG ratio exhibited more blade-like crystals, and the mixed oleogels with MAG: DAG of 3:7 and 5:5 showed altered crystal morphology with finer crystal size and reduced crystallization enthalpies possibly due to the increased nucleation seeds promoted by MAG. The oleogels with high MAG level showed lower equilibrium SFC during isothermal crystallization but faster crystallization rate, higher hardness and elasticity. Therefore, by changing the ratio of DAG with MAG, the crystallization profile and rheological properties of oleogels can be tailored and used as traditional solid fat substitutes in lipid-based products.
Cold-pressed hempseed oil (HSO) is known to have many health benefits due to many phytochemicals and high polyunsaturated fatty acids content. In this study, HSO oleogels were prepared with 3, 5, and 7% natural waxes including sunflower wax (SW), rice bran wax (RBW), beeswax, and candelilla wax to evaluate their potential as solid fat replacements in margarines and spreads. Firmness, crystal structures, and melting properties of these oleogels were evaluated. In general, wax-based HSO oleogels except for RBW-HSO oleogels had lower firmness and weaker crystal network than the corresponding soybean oil (SBO) oleogels. In contrast, RBW-HSO oleogels had similar firmness, comparable or stronger crystal network, and higher melting and crystallization enthalpies compared to those of SBO oleogels. After removing polar compounds from HSO, waxes except for RBW provided oleogels with greater firmness, higher melting and crystallization enthalpies, and stronger crystal network. Therefore, it was concluded that polar compounds negatively affected the physical properties of wax-HSO oleogels but not those of RBW-HSO oleogels. Margarine samples were prepared with SW- and RBW-HSO oleogels, and their firmness and melting properties were examined. The firmness of these margarines indicated that wax-HSO oleogels may achieve the firmness of commercial spreads with less than 3% wax while the firmness of stick margarines cannot be achieved even with 7% wax. Although the properties of wax-HSO oleogels should be further improved, they showed potential as solid fat replacements in margarines and spreads.
Consumers are becoming aware of the relevance of eating low levels of trans and saturated fats in processed foods. In addition, many countries are adopting regulatory measures on the use of these ingredients. For this reason, the exploration of new technologies capable of producing structures that trap liquid oil (composed of unsaturated fatty acids, considered healthier) has been widely investigated in order to replace saturated and trans fats in food products. One of the most promising technologies is the so-called oleogels, which present a great challenge to mimic sensory attributes related to the texture of processed foods based on saturated fats. In this review, we discuss how the different approaches used in the production of oleogels, direct or indirect methods, as well as compositional variables, such as oleogelators and mixing ratio, can directly influence the mechanical properties of these structures. An overview of the parameters that can interfere with these properties contributes to a better understanding of the building of the oleogels and their possible applications.
The structuration processes of mixed oleogels produced with candelilla wax (CW, 0 or 3%), fully hydrogenated soybean oil (FH, 5-15%), and microcrystalline cellulose (MC, 0-9%) were studied to define their rheological effects. During the cooling CW crystals performed as nucleation sites for FH. The elastic modulus (G’) of oleogels with FH and 3% CW were more than two orders of magnitude higher than those produced with 0% CW. Adding MC to the oleogels increased slightly the G’. Independently of the amount of MC, oleogels structured with increasing amounts of FH and 0% CW showed the elastic properties scaling of colloidal gels. This behavior was lost by adding 3% CW, implying that in mixed FH-CW oleogels, the CW crystal network dominated the oleogel rheology. The flow point and the mechanical reversibility of oleogels and commercial butter (CB) was also determined. CB showed flow points at 44 and 59% strain and mechanical reversibility values of 29 and 35% of G’ measured in a pre-shear step. Adding MC to oleogels structured with FH and 0% CW increased their flow point (37.2%) near those of CB. This effect was not produced in mixed FH-3% CW oleogels. The mechanical recovery of oleogels produced with FH, MC, and 0% CW tend to decrease as the FH content increased. CW and MC did not show a simple concentration–effect relationship for the mechanical recovery. Nonetheless, oleogels structured with 3% CW and 10% FH and 6-9% MC showed mechanical recovery (~60%) close to that of CB.
Novel cocoa butter equivalents were designed using dry fractionated Pequi oil and solvent fractionated Kpangnan butter. Static crystallization of binary mixtures of these two fractions into the triclinic form (β2) was achieved after 12 days for all mixtures and after 4 days for the 80:20 w/w and 90:10 w/w fractionated Kpangnan:Pequi oil mixtures. Moreover, after 60 days of storage at 22oC, all binary blends (except 100% fractionated pequi oil and 100% fractionated Kpangnan butter) were crystallized in the most stable triclinic crystal form (β1). Here we also discovered an unusual melting behavior for the fractionaled 30:70 w/w and 20:80 w/w fractionated Kpangnan:Pequi oil mixtures, where after 4 days of static crystallization at room 22oC, these mixtures displayed higher than predicted melting points, 41.89 oC and 33.32 oC, respectively. This suggested a faster kinetics of transformation to the triclinic β2 form for those mixtures. Our results suggest that the 30:70 w/w fractionated Kpangnan:Pequi oil mixture with a melting point of 34oC after 60 days storage at 22oC, a stable triclinic β2 form, and a triglyceride composition of 28% POP, 4.6% POS and 33% SOS displayed solid state characteristics, melting point and crystal structure, of a commercial cocoa butter equivalent.
Silphium integrifolium Michx. (Silflower) has been a promising subject for domestication as a perennial oilseed crop. This work was carried out to investigate the seed processing aspect of this effort. Selected physical properties of the seed were evaluated, seed milling to obtain enriched kernel fraction was conducted, and initial characterization of the seed protein was performed. There was wide variation in flat seed length (11.54 to 20.75 mm), width (4.61 to 11.76 mm), and thickness (0.92 to 1.63 mm). The thousand seed weight was 23.8 g but the tapped bulk density was only 189.58 g/L due to the presence of wing around the seed’s periphery. The kernel accounted for 56.14% of the seed weight and contained 31.00% oil. An enriched kernel fraction with 79.6% purity was obtained by roller-milling, sifting, and air classification. Linoleic (62.3%) and oleic (19.62%) acids were the major fatty acids in the oil. The defatted enriched kernel fraction contained 63.41% crude protein. Globulin, glutelin, albumin, and prolamin accounted for 55.63%, 19.28%, 16.38%, and 8.71% of the soluble proteins, respectively. At an extraction pH of 9, protein solubility was 62%. Maximum solubility (70%) was obtained at pH 10 while minimum solubility of 9% occurred between pH 4 and 5.5. Aside from the oil, the dehulling of silflower seeds also produced a high-protein defatted meal, which may be used as is or as a starting material for enriching the protein further into a protein isolate.
Oil bodies (OBs) are micron- or submicron-sized sub-organelles widely found in plants seeds and nuts. The structure OBs is composed of a core of triglycerides covered by a phospholipid-protein layer, which ensures the stability of the OBs under extreme environmental conditions and further protects core lipids as energy reserves. As naturally pre-emulsified oil-in-water emulsions, OBs have been gradually applied to replace synthetically engineered oil droplets. In this paper, the recent research on the composition, extraction, stability, delivery system, digestion, food applications and future perspectives of plant OBs are reviewed. Recent studies have focused on the OBs surface protein identification and function, large-scale extraction techniques such as enzyme assisted, high pressure, ultrasound, and extrusion and the reconstituted OBs. Electrostatic deposition of polysaccharides significantly improves the stability of OBs emulsions. OBs emulsions have promising applications to encapsulate bioactive compounds, deliver targeted drugs, and prepare gels and edible functional films. The digestive behavior of OBs emulsions is similar to that of protein-stabilized emulsions, which can increase the satiety, effectively help reduce calorie intake and improve the bioavailability of functional factors. It has also promoted the development of simulated dairy, spices and meat products.
Due to its unique triacylglycerol composition, palm oil has the particularity of being semi-solid at room temperature. Major fatty acids are palmitic (P) and oleic (O) types, tripalmitin (P3), oleo-dipalmitin (P2O) and palmito-diolein (PO2) being the most abundant tri-saturated, mono-unsaturated and di-unsaturated triacylglycerols. Palm oil is also the most fractionated oil worldwide, mostly in multi-step operations. Dry fractionation is a process that combines crystallization and separation of partially crystallized oil; in the case of palm oil, the main triacylglycerols involved are obviously P3, P2O and PO2. Crude palm oil is made up of symmetrical and asymmetric isomers and, more particularly, contains POP and OPP in a fixed ratio. This ratio may sometimes be modified during the refining process. Adverse effects of excessive OPP content affect the dry fractionation process and are also reflected in the crystallization properties of the produced solid and liquid fractions. It is therefore fundamental to understand at a molecular level the interactions involved. This paper details and compares the binary phase diagrams of several systems: PPP-POP, PPP-OPP; PPP-POO, POP-POO, OPP-POO and POP-OPP, obtained by combining differential scanning calorimetry and variable temperature powder X-ray diffraction. Co-crystallization properties are analyzed in dynamic mode (heating after quenching) and after tempering (few months stabilization at room temperature). The ternary phase diagrams PPP/POP/POO and PPP/OPP/POO give a complementary representation in terms of isothermal melting lines. Better understanding of these molecular interactions is critical for perspicacious carrying out of the palm oil dry fractionation process.