General approaches to biopolymer-based Pickering emulsions.

Pickering emulsion is a type of emulsion that uses solid particles or colloidal particles as emulsifiers rather than surfactants to adhere at oil-water interface. Pickering emulsions have gathered significant research attention recently due to their excellent stability and wide range of potential uses compared to traditional emulsions. Major advancements have been made in development of innovative Pickering emulsions using different colloidal particles by various techniques including homogenization, emulsification and ultrasonication. Use of biopolymer particles gives Pickering emulsions a more escalating possibilities. In this review paper, we seek to present a critical overview of development in food-grade particles that have been utilized to create Pickering emulsions with a focus on techniques and application of Pickering emulsions. Particularly, we have evaluated protein, lipid, polysaccharide-based particles and microalgal proteins that have emerged in recent years with respect to their potential to stabilize and add novel functionalities to Pickering emulsions. Some preparation methods of Pickering emulsions in brief, applications of Pickering emulsions are also highlighted. Encapsulation and delivery of bioactive compounds, fat substitutes, film formation and catalysis are potential applications of Pickering emulsions. Pickering double emulsions, nutraceutical and bioactive co-delivery, and preparation of porous materials are among research trends of food-grade Pickering emulsions.

Ultrasonication as an innovative approach to tailor the apple seed proteins into nanosize: Effect on protein structural and functional properties.

In this study, protein was extracted from the apple seed flour using alkali-acid precipitation method. The main objective of this study was to evaluate the impact of ultrasonication on structural and techno-functional properties of apple seed protein. Both native (N-protein) and ultra-sonicated protein (US-protein) were characterized for size, zeta potential, structure, protein pattern, crystallinity, thermal stability and functional properties. The results revealed that the hydrodynamic diameter of N-protein and US-protein was 1.2 µm and 484 nm while zeta potential was -11 and -19 mV, respectively. Fourier transform infrared-spectroscopy and X-ray diffraction analysis showed change in the conformational characteristics and functional groups of proteins after nano-reduction. SEM revealed change in the surface morphology of protein molecule upon ultrasonication. Differential scanning calorimetry showed decreased denaturation temperature for US-protein compared to N-protein . SDS-PAGE depicted no change in protein pattern upon ultrasonication. Ultrasonicated protein exhibited increased functional properties like emulsification, foaming, hydrophobicity and oil absorbing properties and hence can be efficiently used as functional ingredient in food and nutraceutical industry.

Nano reduction coupled with encapsulation as a novel technique for utilising millet proteins as future foods.

Crocin (saffron bioactive) loaded protein nanoparticles were prepared from three underutilised cereal varieties viz., sorghum (SPCN), foxtail millet (FPCN) and pearl millet (PPCN) using ultrasonication technique. The particle size of crocin loaded protein complex was attained in the nano range with reduced polydispersity index and negative zeta potential. The encapsulation efficiency of crocin in protein nanoparticles was found to be 83.78% (FPCN), 78.74 % (SPCN) and 70.01% (PPCN). The topographical images of crocin loaded protein nano complex was revealed using field emission-scanning electron microscopy (FE-SEM). The attenuated total reflectance fourier transform infra-spectroscopy (ATR-FTIR) analysis showed the characteristic peaks of crocin at 956, 1700 and 3350 cm-1 in protein-crocin nanocomplex as a confirmatory test for nanoencapsulation. The antimicrobial activity of crocin loaded protein nanocomplex against three strains (Escherichia coli, Staphylococcus aureus and Fusarium oxysporium) were also evaluated. In vitro release studies showed higher content of crocin released in simulated intestinal conditions ensuring its controlled release at target site. Bioactivity (anti-cancerous and anti-hypertensive) of crocin upon in-vitro digestion were well retained indicating that protein nanoparticles can act as an effective wall material. Our results suggest that protein nanoparticles prepared in this study can act as an effective oral delivery vehicle for crocin that could be used for development of functional foods.

Ferulic acid loaded pickering emulsions stabilized by resistant starch nanoparticles using ultrasonication: Characterization, in vitro release and nutraceutical potential.

The use of starch based nanoparticles have gained momentum in stabilizing pickering emulsions for it's numerous advantages. In present study resistant starch (RS) was isolated from lotus stem using enzymatic digestion and subjected to nanoprecipitation and ultrasonication to yield resistant starch nanoparticles (RSN). RSN of varying concentrations (2%, 10% and 20%) were used to stabilize the flax seed-oil water mixture to form pickering emulsions. The emulsions were used to nanoencapsulate ferulic acid (FA) - a well known bioactive via ultrasonication. The emulsions were lyophilized to form FA loaded lyophilized pickering emulsion (FA-LPE). The FA-LPE (2%, 10 % and 20%) were characterized using dynamic light scattering (DLS), light microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and attenuated total reflectance fourier transform infra-spectroscopy (ATR-FTIR). AFM showed FA-LPE as spherical droplets embedded in the matrix with maximum peak height of 8.47 nm and maximum pit height of 1.69 nm. SEM presented FA-LPE as an irregular and continuous surface having multiple folds and holes. The ATR-FTIR spectra of all the samples displayed peaks of C = C aromatic rings of FA at 1600 cm-1 and 1439 cm-1, signifying successful encapsulation. In vitro release assay displayed more controlled release of FA from FA-LPE (20%). Bioactivity of FA-LPE was evaluated in terms of anti-cancer, anti-diabetic, angiotensin converting enzyme (ACE) inhibition and prevention against oxidative damage under simulated gastro-intestinal conditions (SGID). The bioactivity of FA-LPE (20%) was significantly higher than FA-LPE (2%) and FA-LPE (10%). Key findings reveal that pickering emulsions can prevent FA under harsh SGID conditions and provide an approach to facilitate the design of pickering emulsions with high stability for nutraceutical delivery in food and supplement products.

Ultrasonics as a tool for development of pine-needle extract loaded bee wax edible packaging for value addition of Himalayan cheese.

In the present study, Himalayan cheese, kradi was coated with beeswax loaded with pine needle extract (PNE) to increase its shelf life and nutraceutical potential. PNE was extracted via ultrasonication and incorporated into beeswax at concentrations, 2:1, 1:1, and 2:3 (grams of beeswax to mL of PNE). The dispersion of PNE in the coatings was carried out using an ultrasonic probe at a frequency of 20 kHz for 15 min and at power rating of 500 W. The coatings were characterised using scanning electron microscopy, light microscopy, dynamic light scattering (DLS), fourier transmission infrared spectroscopy. DLS revealed a hydrodynamic diameter and zeta potential of 12.11 ± 0.41 µm and -19.32 ± 0.61 mV for coating loaded with highest concentration of PNE. The bioactivities of the coating including antioxidant, antidiabetic and antibacterial assays revealed significantly higher values with the increase in PNE concentration. Shelf life and sensory evaluation study including microbiological and sensory analysis revealed inhibition of mould growth and good score of texture and appearance with the increase in concentration of PNE. The study provides a future perspective for application of beeswax loaded PNE coatings in cheese industry.

Resistant starch type 2 from lotus stem: Ultrasonic effect on physical and nutraceutical properties.

Resistant starch type 2 (RS) was isolated from lotus stem using enzymatic digestion method. The isolated RS was subjected to ultrasonication (US) at different sonication power (100-400 W). The US treated and untreated RS samples were characterized using dynamic light scattering (DLS), scanning electron microscopy (SEM), light microscopy and Fourier transform infrared spectroscopy (FT-IR). DLS revealed that particle size of RS decreased from 12.80 µm to 413.19 nm and zeta potential increased from -12.34 mV to -26.09 mV with the increase in sonication power. SEM revealed smaller, disintegrated and irregular shaped RS particles after ultrasonication. FT-IR showed the decreased the band intensity at 995 cm-1 and 1047 cm-1 signifying that US treatment decreased the crystallinity of RS and increased its amorphous character. The bile acid binding, anti-oxidant and pancreatic lipase inhibition activity of samples also increased significantly (p < 0.05) with the increase in sonication power. Increase in US power however increased the values of hydrolysis from 23.11 ± 1.09 to 36.06 ± 0.13% and gylcemic index from 52.39 ± 0.38 to 59.50 ± 0.11. Overall, the non-thermal process of ultrasonic treatment can be used to change the structural, morphological and nutraceutical profile of lotus stem resistant starch which can have great food and pharamaceutical applications.

Valorization of natural colors as health-promoting bioactive compounds: Phytochemical profile, extraction techniques, and pharmacological perspectives.

Color is the prime attribute with a large impact on consumers' perception, selection, and acceptance of foods. However, the belief in bio-safety protocols, health benefits, and the nutritional importance of food colors had focused the attention of the scientific community across the globe towards natural colorants that serve to replace their synthetic toxic counterparts. Moreover, multi-disciplinary applications of greener extraction techniques and their hyphenated counterparts for selective extraction of bioactive compounds is a hot topic focusing on process intensification, waste valorization, and retention of highly stable bioactive pigments from natural sources. In this article, we have reviewed available literature to provide all possible information on various aspects of natural colorants, including their sources, photochemistry and associated biological activities explored under in-vitro and in-vivo animal and human studies. However a particular focus is given on innovative technological approaches for the effective extraction of natural colors for nutraceutical and pharmaceutical applications.

Characterisation and utilisation of nano-reduced starch from underutilised cereals for delivery of folic acid through human GI tract.

Ball milling offers green approach for size reduction of starch granules to nano scale size. In this research work, the starch from two underutilised cereal varieties viz. foxtail starch (FS) and sorghum starch (SS) were milled to achieve the desired nanometric range with mean particle diameter of 467.98 and 271.12 nm for nano foxtail (FSN) and nano sorghum starch (SSN), which were highly stable as revealed by zeta potential analysis. Functional attributes like solubility, swelling index, apparent amylose content, emulsifying and pasting properties were evaluated. Scanning electron microscopy (SEM) clearly revealed damaged starch granules produed by the process of milling. X-ray diffraction (XRD) displayed decrease in crystallinity upon milling to 16.08% (SSN) and 18.56% (FSN) and disappearance of some peaks. Attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) also revealed reduced crystallinity as confirmed by the decreased absorbance ratio of 1047/1022 cm-1 in nano starch particles. Rheological analysis displayed shear thinning behaviour of nano starch samples as evaluated using Herschel-bulkely model and Power law. The nano starch samples exhibited comparatively low thermal gelatinisation temperatures as compared to native counter particles. Moreover, the nano-encapsulated starch samples offered more resistance to in-vitro digestion and showed control release of folic acid at target sites.

Exploitation of polyphenols and proteins using nanoencapsulation for anti-viral and brain boosting properties - Evoking a synergistic strategy to combat COVID-19 pandemic.

The world is currently under the threat of COVID pandemic and has focused every dimension of research in finding a cure to this novel disease. In this current situation, people are facing mental stress, agony, fear, depression and other associated symptoms which are taking a toll on their overall mental health. Nanoencapsulation of certain brain boosting polyphenols including quercetin, caffeine, cocoa flavanols and proteins like lectins can become new area of interest in the present scenario. Besides the brain boosting benefits, we have also highlighted the anti- viral activities of these compounds which we assume can play a possible role in combating COVID-19 given to their previous history of action against certain viruses. This review outlines the nanoencapsulation approaches of such synergistic compounds as a novel strategy to take the ongoing research a step ahead and also provides a new insight in bringing the role of nanotechnology in addressing the issues related to COVID pandemic.

Nanoreduction as a technology to exploit ß-Glucan from cereal and fungal sources for enhancing its nutraceutical potential.

ß-Glucan nanoparticles were produced from cereal and fungal sources viz: oats, barley, and yeast using ball milling which is considered as a green technology. The ß-glucan nanoparticles were evaluated using dynamic light scattering (DLS) and Fourier transform infra-spectroscopy (ATR-FTIR). The particle size, zeta potential, polydispersity index, antioxidant, anticancerous, antimicrobial and antihypertensive potential of ß-glucan nanoparticles from different sources were also studied. The experimental results revealed that the average particle size for BN (Barley ß-glucan nanoparticle), ON (Oats ß-glucan nanoparticle), and YN (Yeast ß-glucan nanoparticle) were 90.35, 83.55 and 77.44 nm and zeta potential were in the range of -27 to -6.3 mV. . There was an increase in antioxidant, antihyperglycemic and antihypertensive activity of BN, YN, and ON in comparison to native. Study reported increase in anticancerous activity upon size reduction. Also, antibacterial activity of BNT, ONT, YNT, BN, ON and YN against Gram-negative and Gram-positive (E.coli & Bacillus Subtilis) were studied. It was concluded that the ß-glucan nanoparticles showed enhanced nutraceutical properties that might be due to the nanoreduction using green technology.

Nano-reduction of starch from underutilised millets: Effect on structural, thermal, morphological and nutraceutical properties.

Starch nanoparticles from pearl (Pe) and proso (Pr) millets were characterised for morphological, thermal, rheological and nutraceutical properties which are important parameters to be considered for predicting applicable domain of nanoparticles in food and other industrial applications. In the present study after using collision ball milling to achieve the nano-reduction, dynamic light scattering (DLS) revealed the average hydrodynamic particle diameter of 636 nm and 417 nm for nano-reduced pearl (PeN) and proso (PrN) millet starches. Further the nano-particles produced were having greater stability, as revealed by the data obtained for zeta potential. X-ray diffraction (XRD) revealed loss of crystallinity in starch granules whereas attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) showed no difference in the basic functional groups but decrease in intensity. Scanning electron microscopy (SEM) was used to elicit the changes in surface topography of starch granules upon nano-reduction. Post nano-reduction treatment various thermal transition temperatures significantly shifted to lower values. Results of anti-oxidant assays for prediction of nutraceutical potential revealed significant increase upon nano-reduction.