Perspectives on Saponins: Food Functionality and Applications.

Saponins are a diverse group of naturally occurring plant secondary metabolites present in a wide range of foods ranging from grains, pulses, and green leaves to sea creatures. They consist of a hydrophilic sugar moiety linked to a lipophilic aglycone, resulting in an amphiphilic nature and unique functional properties. Their amphiphilic structures enable saponins to exhibit surface-active properties, resulting in stable foams and complexes with various molecules. In the context of food applications, saponins are utilized as natural emulsifiers, foaming agents, and stabilizers. They contribute to texture and stability in food products and have potential health benefits, including cholesterol-lowering and anticancer effects. Saponins possess additional bioactivities that make them valuable in the pharmaceutical industry as anti-inflammatory, antimicrobial, antiviral, and antiparasitic agents to name a few. Saponins can demonstrate cytotoxic activity against cancer cell lines and can also act as adjuvants, enhancing the immune response to vaccines. Their ability to form stable complexes with drugs further expands their potential in drug delivery systems. However, challenges such as bitterness, cytotoxicity, and instability under certain conditions need to be addressed for effective utilization of saponins in foods and related applications. In this paper, we have reviewed the chemistry, functionality, and application aspects of saponins from various plant sources, and have summarized the regulatory aspects of the food-based application of quillaja saponins. Further research to explore the full potential of saponins in improving food quality and human health has been suggested. It is expected that this article will be a useful resource for researchers in food, feed, pharmaceuticals, and material science.

Rheological and Microstructural Characteristics of Canola Protein Isolate-Chitosan Complex Coacervates.

Wastage of byproducts such as canola meal is a pressing environmental concern, and canola protein isolate (CPI)-chitosan (Ch) coacervates have a good potential to utilize and convert the wastes into a high value added product. Yet so far, there is very limited rheological and microstructural information to assist in proper utilization of CPI -Ch complex coacervates. The rheological and microstructural properties of the complex coacervates formed from CPI and chitosan Ch at various CPI-to-Ch mixing ratios (1:1, 16:1, 20:1, and 30:1) and pH values (5.0, 6.0, and 7.0) were therefore investigated. These CPI-Ch complex coacervate phases were found to exhibit elastic behavior as evidenced by significantly higher elastic modulus (G') compared to viscous modulus (G″) in all the tested ratios and pH ranges. They also exhibited shear-thinning behavior during viscous flow. The complex coacervates formed at the optimum CPI-to-Ch ratio of 16:1 and pH of 6.0 demonstrated the highest G', G″, and shear viscosity, which correlated well with the high strength of electrostatic interaction and thick-walled, sponge-like, less-porous microstructure at this condition. The higher shear viscosity of the coacervate at pH 6.0 was most likely induced by stronger attractive electrostatic interactions between CPI and Ch molecules, due to the formation of a rather densely packed complex coacervate structure. Hence, it can be concluded that the microstructural observations of denser structure correlated well with the rheological findings of stronger intermolecular bonds at the optimum CPI-to-Ch ratio of 16:1 and pH of 6.0. The complex coacervate phase formed at a CPI-to-Ch ratio of 16:1 and pH of 6.0 also showed glassy consistency at low temperatures and rubbery consistency above its glass-transition temperature. This study identified the potential for the newly developed CPI-Ch complex coacervate to be used as an encapsulating material due to its favorable strength. This would drastically reduce the wastage of byproducts, provide a solution to tackle the pressing global issue of wastage of byproducts, and bring about a more environmentally friendly paradigm.

Investigation of oil distribution in spray-dried chia seed oil microcapsules using synchrotron-FTIR microspectroscopy.

In this study, chia seed oil (CSO) microcapsules were produced using three types of shell materials, including chia seed protein (CPI), chia seed gum (CSG) and CPI-CSG complex coacervates. Synchrotron-Fourier transform infrared (S-FTIR) microspectroscopy was used to investigate the effect of shell materials on the distribution of CSO both on the surface and in the interior of the solid microcapsules. S-FTIR measurements were carried out in macroscopic attenuated total reflection (macro ATR) and transmission modes, to determine the surface lipid and the encapsulated lipid fractions, respectively. The amounts of lipid and protein distributed on the surface and in the interior of the microcapsules were compared based on the average spectra extracted from S-FTIR chemical images obtained from each type of the microcapsules. The unsaturated fatty acids (UFAs) to total oil ratios in all the three types of the microcapsules were closely similar to the original non-processed CSO, suggesting an effective encapsulation and thereby shielding protection of UFAs from oxidative damage during microencapsulation process. The type of the shell materials was found to affect the distribution of CSO on the surface and within the microcapsules. The complex coacervation based microcapsules had a significantly lower oil content (∼2% w/w) on the surface compared to those observed for the other two types of microcapsules (>5%, w/w).

Lactoferrin: Structure, function, denaturation and digestion.

Lactoferrin (LF) is a multifunctional protein occurring in many biological secretions including milk. It possesses iron binding/transferring, antibacterial, antiviral, antifungal, anti-inflammatory and anti-carcinogenic properties. These functional properties intimately depend on the structural integrity of LF especially its higher order conformation. LF is primarily extracted from bovine milk and it is subsequently added into many commercial products such as nutritional supplements, infant formula, cosmetics and toothpaste. LF is sensitive to denaturation induced by temperature and other physicochemical stresses. Hence, the extraction, powder formation processes of LF and processing parameters of LF-containing products have to be optimized to minimise its undesired denaturation. This review documents the advances made on structure-function relationships and discusses the effectiveness of methods used to preserve the structure of LF during thermal processing. Oral delivery, as the most convenient way for administering LF, is also discussed focusing on digestion of LF in oral, gastric and intestinal stages. The effectiveness of methods used to deliver LF to intestinal digestion stage in structurally intact form is also compared. Altogether, this work comprehensively reviews the fate of LF during thermal processing and digestion, and suggests suitable means to preserve its structural integrity and functional properties. Scope of review The manuscript aims at providing a comprehensive review of the latest publications on four aspects of LF: structural features, functional properties, nature and extent of denaturation and gastrointestinal digestion. It also analyses how these publications benefit food and pharmaceutical industries.

Complex coacervation: Principles, mechanisms and applications in microencapsulation.

Complex coacervation is a highly promising microencapsulation technique that is extensively employed in pharmaceutical, food, agriculture and textile industries. The process involves the interaction of oppositely charged polyelectrolytes in aqueous form. High payload and high encapsulation efficiency (up to 99%), relatively lower cost of processing, ability to use food-grade shell materials and synthesis at ambient temperature makes coacervation an appropriate choice in food and agrochemical industries. Various works have been documented using different polymer systems and core-shell combinations. This review paper intends to summarize some of the recent advances in complex coacervation for use in the food and agriculture areas. Current status and future trends of plant proteins utilization for complex coacervation have been reviewed. It is expected that this review will be a useful resource for material scientists, food technologists and food engineers.

Star Anise (Illicium verum Hook. f.) as Quorum Sensing and Biofilm Formation Inhibitor on Foodborne Bacteria: Study in Milk.

Bacteria use quorum sensing (QS) systems to communicate with each other and regulate microbial group behavior, such as the secretion of virulence factors, including biofilm formation. In order to explore safe, edible agents, the potential of star anise (SA) as an anti-QS and antibiofilm agent and its possible application in milk safety were investigated. Staphylococcus aureus , Salmonella Typhimurium, Pseudomonas aeruginosa , and biosensor strain Chromobacterium violaceum were selected as test strains for QS, biofilm, and exopolysaccharide assays. The percent acidities and total plate counts were determined to evaluate the quality of biofilm-inoculated and noninoculated milk. The yield of SA extraction was 25.90% ± 0.2% (w/w). At sub-MIC, SA extract did not show any effect on bacterial growth. The production of violacein was inhibited by 89% by SA extract. The extract also inhibited the formation of biofilm by up to 87% in a dose-dependent manner. Inhibition rates of 70.45%, 42.82%, and 35.66% were found for exopolysaccharide production. The swarming motility of S. aureus was reduced by about 95.9% by SA extract. Confocal laser scanning microscopy analysis confirmed that the development of biofilm architecture was hampered. It was found that SA extract could delay the spoilage of milk. In the endeavor to avoid drug resistance, pathogenesis, and resistance to biocides while improving food safety and avoiding health hazard issues arising from synthetic chemicals, SA extract could be used as a potential QS and biofilm inhibitor.

Physicochemical and thermal characteristics of Australian chia seed oil.

Physicochemical and thermal characteristics of Australian chia seed oil (CSO) were studied. The specific gravity, viscosity and refractive index of CSO at ambient temperature were 0.93, 43.2mPa.s and 1.48, respectively. The acid, peroxide, saponification and iodine values and unsaponifiable matter content of CSO were 2.54gKOH/kg oil, 4.33meqO2/kg oil, 197gKOH/kg oil, 204gI2/kg oil and 1.12%, respectively. α-linolenic acid is the most abundant fatty acid comprising (64.39% of total oil) followed by linoleic acid (21.46%), while saturated fatty acid content is less than 10%. This CSO contained twelve triacylglycerols (TAGs) out of which trilinolenin (αLnαLnαLn) was the most abundant comprising 33.2% of total TAG. Melting point and melting enthalpy of CSO were -34°C and 77.48J/g, respectively. CSO remained stable up to 300°C with negligible degradation. Due to these physicochemical and thermal properties, CSO is an excellent source of essential fatty acids for food industries.

Characteristics of bovine lactoferrin powders produced through spray and freeze drying processes.

Bovine lactoferrin (LFb) powders were produced using spray drying and freeze drying. Industrially obtained fresh liquid-LFb was used as starting material. The antioxidant capacity, solubility in water, moisture sorption behaviour, the extent of denaturation and changes in the secondary structural features of spray-dried (SDLFb) and freeze-dried bovine lactoferrin (FDLFb) powders were determined. The residual moisture content, water activity, particle size and amorphous/crystalline nature of the SDLFb and FDLFb were also measured. Results showed that both SDLFb and FDLFb powders had negligible denaturation and conformation changes compared to the liquid-LFb. Both SDLFb and FDLFb showed type II sorption behaviour with almost identical monolayer moisture content. The SDLFb powders were amorphous in nature with >98% solubility in water. The antioxidant activity of SDLFb was similar to that of the liquid-LFb while it was ∼6% less in FDLFb. Based on the residual moisture content, water activity, solubility and preservation of secondary structure of LFb in resultant powders, a spray drying process with 180°C inlet and 95°C outlet temperature was found to produce similar or better quality LFb powders compared to the ones produced through a freeze drying process.

Physicochemical and functional properties of protein isolate produced from Australian chia seeds.

Protein was isolated from Australian chia seeds and converted to powders using spray, freeze and vacuum drying methods, to investigate the effect of drying methods on physicochemical and functional attributes of chia-seed protein isolate (CPI). It was found that there was no significant difference in the proximate composition; however vacuum dried CPI (VDCPI) had the highest bulk density and oil absorption capacity, whereas spray dried powder (SDCPI) demonstrated the highest solubility, water absorption capacity and lowest surface hydrophobicity. Solubility of all powders was higher at elevated temperature and alkaline pH. Foaming capacity and foam stability of CPI were found to increase with increasing pH and protein concentration. SDCPI was the least denatured and VDCPI the most denatured, demonstrating the poorest solubility and foaming properties of the latter. These findings are expected to be useful in selection of a drying process to yield chia seed protein powders with more desirable functionality.

Microencapsulation of chia seed oil using chia seed protein isolate-chia seed gum complex coacervates.

Chia seed oil (CSO) microcapsules were produced by using chia seed protein isolate (CPI)-chia seed gum (CSG) complex coacervates aiming to enhance the oxidative stability of CSO. The effect of wall material composition, core-to-wall ratio and method of drying on the microencapsulation efficiency (MEE) and oxidative stability (OS) was studied The microcapsules produced using CPI-CSG complex coacervates as wall material had higher MEE at equivalent payload, lower surface oil and higher OS compared to the microcapsules produced by using CSG and CPI individually. CSO microcapsules produced by using CSG as wall material had lowest MEE (67.3%) and oxidative stability index (OSI=6.6h), whereas CPI-CSG complex coacervate microcapsules had the highest MEE (93.9%) and OSI (12.3h). The MEE and OSI of microcapsules produced by using CPI as wall materials were in between those produced by using CSG and CPI-CSG complex coacervates as wall materials. The CSO microcapsules produced by using CPI-CSG complex coacervate as shell matrix at core-to-wall ratio of 1:2 had 6 times longer storage life compared to that of unencapsulated CSO. The peroxide value of CSO microcapsule produced using CPI-CSG complex coacervate as wall material was <10meq O2/kg oil during 30 days of storage.

Molecular and functional characteristics of purified gum from Australian chia seeds.

Chia seed gum (CSG) was extracted from the seed coat of Salvia hispanica, purified in the laboratory and its chemical composition and functional properties were investigated. CSG was found to comprise 93.8% carbohydrate consisting of xylose, glucose, arabinose, galactose, glucuronic acid and galacturonic acid as monosaccharide units. The presence of uronic acids was reflected in the anionic behavior of the CSG solution over a wide range of pH (≥ 1.8). The solubility of CSG increased slightly with temperature and pH of the aqueous medium. CSG was able to resist pyrolytic decomposition at temperatures well in excess of 250 °C, and exhibited a high water holding capacity (23 times of its own weight). The surface activity and emulsifying properties of CSG were found to be either superior or comparable to other common gums and industrial polysaccharides indicating the potential of CSG as an effective thickener and stabilizer of processed foods.

Rheological and microstructural properties of the chia seed polysaccharide.

Chia seed polysaccharide (CSP) was extracted from chia (Salvia hispanica) seeds, and its rheological and microstructural properties in aqueous solutions were studied. CSP solution exhibited Newtonian and shear thinning flow patterns depending on shear rate when the concentration was ≤0.06% (w/v). CSP solutions at concentrations >0.06% (w/v) exhibited strong shear thinning behaviour within the shear rate tested (0.001-300s(-1)). The transition from dilute to semi-dilute regime occurred at a critical concentration (C*) of 0.03gdL(-1). The intrinsic viscosity was high (∼16dLg(-1)) and concentration dependence of zero shear viscosity in the semi-dilute regime followed η0∝C(2.7) relationship. The storage modulus (G') was higher than the loss modulus (G″) at all experimental frequencies and their frequency dependence was negligible at all tested concentrations. Apparent shear viscosity was smaller than dynamic complex viscosity at equivalent values of deformation and G' varied with the square of concentration indicating a gel-like behaviour in CSP solutions within 0.02-3.0% (w/v) concentrations. Controlled acid hydrolysis of purified CSP yielded various low molecular fractions with fairly uniform polydispersity giving a Mark-Houwink-Sakurada relationship of intrinsic viscosity equaling to 1.52×10(-4) (molecular weight)(0.803) (dLg(-1)).

Enhanced efficiency fertilisers: a review of formulation and nutrient release patterns.

Fertilisers are one of the most important elements of modern agriculture. The application of fertilisers in agricultural practices has markedly increased the production of food, feed, fuel, fibre and other plant products. However, a significant portion of nutrients applied in the field is not taken up by plants and is lost through leaching, volatilisation, nitrification, or other means. Such a loss increases the cost of fertiliser and severely pollutes the environment. To alleviate these problems, enhanced efficiency fertilisers (EEFs) are produced and used in the form of controlled release fertilisers and nitrification/urease inhibitors. The application of biopolymers for coating in EEFs, tailoring the release pattern of nutrients to closely match the growth requirement of plants and development of realistic models to predict the release pattern of common nutrients have been the foci of fertiliser research. In this context, this paper intends to review relevant aspects of new developments in fertiliser production and use, agronomic, economic and environmental drives for enhanced efficiency fertilisers and their formulation process and the nutrient release behaviour. Application of biopolymers and complex coacervation technique for nutrient encapsulation is also explored as a promising technology to produce EEFs.

Effect of different pretreatments on delignification pattern and enzymatic hydrolysability of miscanthus, oil palm biomass and typha grass.

Cumulative pretreatments methods were evaluated for delignification ability and enzymatic digestibility using miscanthus (M×G), empty palm fruit bunch (EFB) and typha grass as feedstocks. Despite their close chemical composition, the three feedstocks unveiled quite different behavior under the same condition of pretreatment. Characterization of ethanol organosol lignins extracted from the three feedstocks by (13)C NMR and FTIR revealed information concerning S/G/H ratios which was important to rationalize the differences among the feedstock behavior. The S/G/H ratios for MxG, EFB and typha, were established to levels of ~52/44/4, ~68/30/2 and ~46/27/27 respectively. The xylans hydrolytic susceptibility were a major cause of difference in behavior of feedstock during the pretreatment process. The influence of the presence of naphthol during autohydrolysis on the delignification ability was studied. A good relationship was observed between S+H/G ratio and the scavenging effect of naphthol.