The application of starch-based ingredients in flavor encapsulation

Potential use of Thai mango (Mangifera indica Linn. cultivar Chok-Anan) seed porous starch for retention of aroma compounds from coffee extract

This study aimed to extract and modify the properties of the starch from Thai mango seeds (cultivar Chok-Anan). The porous starch samples were obtained using enzymatic treatment and its potential to retain aroma compounds from coffee extract was evaluated. The physicochemical properties, structure characteristics, porosity characteristics and adsorption quantity of starches were also determined. The retention of coffee aroma compounds was investigated through combining starch or porous starch with odorants, and storing the mixtures at room temperature for 7 and 14 days, respectively. The chemical properties of aroma compounds as well as starch surface properties were observed to affect the retention of aroma compounds upon storage. Additionally, 2-furanmethanol, d-limonene and maltol were selected to be the primary target compounds to assess the retention of odorants. This study observed a noticeable decrease in d-limonene content throughout the storage period. On the contrary, after 14 days of storage, the porous starch exhibited high retention of hydroxy compounds including 2-furanmethanol and maltol. However, after prolonged storage their ability to retain 2-furanmethanol and maltol slightly decreased. Therefore, the porous starch derived from mango seeds exhibited the potential to retain coffee aroma compounds and could be a desirable green adsorbent for food and cosmetic industries.

Formation, influencing factors, and applications of internal channels in starch: A review

Starch, a natural polymer, has a complex internal structure. Some starches, such as corn and wheat starches, have well-developed surface pores and internal channels. These channel structures are considered crucial in connecting surface stomata and internal cavities and have adequate space for loading guest molecules. After processing or modification, the starch-containing channel structures can be used for food and drug encapsulation and delivery. This article reviews the formation and determination of starch internal channels, and the influence of different factors (such as starch species and processing conditions) on the channel structure. It also discusses relevant starch preparation methods (physical, chemical, enzymatic, and synergistic), and the encapsulation effect of starch containing internal channels on different substances. In addition, the role of internal channels in regulating the starch digestion rate and other aspects is also discussed here. This review highlights the significant multifunctional applications of starch with a channel structure.

Expanded porous-starch matrix as an alternative to porous starch granule: Present status, challenges, and future prospects

Exposing the hydrated-soft-starch matrix of intact grain or reconstituted flour dough to a high-temperature-short-time (HTST) leads to rapid vapor generation that facilitates high-pressure build-up in its elastic matrix linked to large deformation and expansion. The expanded starch matrix at high temperatures dries up quickly by flash vaporization of water, which causes loss of its structural flexibility and imparts a porous and rigid structure of the expanded porous starch matrix (EPSM). EPSM, with abundant pores in its construction, offers adsorptive effectiveness, solubility, swelling ability, mechanical strength, and thermal stability. It can be a sustainable and easy-to-construct alternative to porous starch (PS) in food and pharmaceutical applications. This review is a comparative study of PS and EPSM on their preparation methods, structure, and physicochemical properties, finding compatibility and addressing challenges in recommending EPSM as an alternative to PS in adsorbing, dispersing, stabilizing, and delivering active ingredients in a controlled and efficient way.

Characterization of a Novel Starch Isolated from the Rhizome of Colombian Turmeric (Curcuma longa L.) Cultivars

Turmeric (Curcuma longa L.) plants are native to Southeast Asia and are part of the Zingiberaceae family. Global consumption and production of this plant are expanding. In countries such as Colombia, turmeric is a promising cultivar. Curcuminoids derived from its rhizomes are used in food, pharmaceuticals, and natural cosmetics. Curcuminoids constitute approximately 3 wt% of the rhizome. Many residues rich in cellulose and starch can thus be recovered. This study characterizes a novel starch isolated from Colombian turmeric cultivars. The morphological parameters of the starch were determined using microscopic techniques such as scanning electron microscopy (SEM). Proximate analysis and infrared spectroscopy (ATR-FTIR) were used to analyze the chemical composition, while physical analyses included thermal characterization, swelling power testing, solubility, water retention capacity, and colorimetry evaluation. The new starch granules were ellipsoidal in shape and ranged in diameter from 19.91 to 38.09. A trace amount of remaining curcumin was identified through chemical and physical characterization. The swelling power was 3.52 ± 0.30, and its water retention capacity was 3.44 ± 0.30. Based on these findings, turmeric can be useful in both food and non-food applications. Because starch was extracted from other Zingiberaceae plants, this study also includes a brief review of the related literature.

Research progress of starch as microencapsulated wall material

Starch is non-toxic, low cost, and possesses good biocompatibility and biodegradability. As a natural polymer material, starch is an ideal choice for microcapsule wall materials. Starch-based microcapsules have a wide range of applications and application prospects in fields such as food, pharmaceuticals, cosmetics, and others. This paper firstly reviews the commonly used wall materials and preparation methods of starch-based microcapsules. Then the effect of starch wall materials on microcapsule properties is introduced in detail. It is expected to provide researchers with design inspiration and ideas for the development of starch-based microcapsules. Next the applications of starch-based microcapsules in various fields are presented. Finally, the future trends of starch-based microcapsules are discussed. Molecular simulation, green chemistry, and solutions to the main problems faced by resistant starch microcapsules may be the future research trends of starch-based microcapsules.

Flavor-food ingredient interactions in fortified or reformulated novel food: Binding behaviors, manipulation strategies, sensory impacts, and future trends in delicious and healthy food design

With consumers gaining prominent awareness of health and well-being, a diverse range of fortified or reformulated novel food is developed to achieve personalized or tailored nutrition using protein, carbohydrates, or fat as building blocks. Flavor property is a critical factor in the acceptability and marketability of fortified or reformulated food. Major food ingredients are able to interact with flavor compounds, leading to a significant change in flavor release from the food matrix and, ultimately, altering flavor perception. Although many efforts have been made to elucidate how food matrix components change flavor binding capacities, the influences on flavor perception and their implications for the innovation of fortified or reformulated novel food have not been systematically summarized up to now. Thus, this review provides detailed knowledge about the binding behaviors of flavors to major food ingredients, as well as their influences on flavor retention, release, and perception. Practical approaches for manipulating these interactions and the resulting flavor quality are also reviewed, from the scope of their intrinsic and extrinsic influencing factors with technologies available, which is helpful for future food innovation. Evaluation of food-ingredient interactions using real food matrices while considering multisensory flavor perception is also prospected, to well motivate food industries to investigate new strategies for tasteful and healthy food design in response to consumers' unwillingness to compromise on flavor for health.

Efficient strategies for controlled release of nanoencapsulated phytohormones to improve plant stress tolerance

Climate change due to different human activities is causing adverse environmental conditions and uncontrolled extreme weather events. These harsh conditions are directly affecting the crop areas, and consequently, their yield (both in quantity and quality) is often impaired. It is essential to seek new advanced technologies to allow plants to tolerate environmental stresses and maintain their normal growth and development. Treatments performed with exogenous phytohormones stand out because they mitigate the negative effects of stress and promote the growth rate of plants. However, the technical limitations in field application, the putative side effects, and the difficulty in determining the correct dose, limit their widespread use. Nanoencapsulated systems have attracted attention because they allow a controlled delivery of active compounds and for their protection with eco-friendly shell biomaterials. Encapsulation is in continuous evolution due to the development and improvement of new techniques economically affordable and environmentally friendly, as well as new biomaterials with high affinity to carry and coat bioactive compounds. Despite their potential as an efficient alternative to phytohormone treatments, encapsulation systems remain relatively unexplored to date. This review aims to emphasize the potential of phytohormone treatments as a means of enhancing plant stress tolerance, with a specific focus on the benefits that can be gained through the improved exogenous application of these treatments using encapsulation techniques. Moreover, the main encapsulation techniques, shell materials and recent work on plants treated with encapsulated phytohormones have been compiled.

Microencapsulation with Different Starch-Based Polymers for Improving Oxidative Stability of Cold-Pressed Hickory (Carya cathayensis Sarg.) Oil

Hickory (Carya cathayensis Sarg.) oil is a nutrient-dense edible woody oil, with its unsaturated fatty acids accounting for more than 90% of total ones, and liable to oxidation spoilage. To efficiently improve its stability and expand its application fields, the microencapsulation of cold-pressed hickory oil (CHO) by the molecular embedding method and freeze-drying technique was performed using malt dextrin (MD), hydroxylpropyl-β-cyclodextrin (HP-β-CD), β-cyclodextrin (β-CD), or porous starch (PS) as a wall material. Two wall materials and/or their CHO microcapsulates (CHOM) with higher encapsulation efficiencies (EE) were selected to carry out physical and chemical characterizations using laser particle size diffractometer, scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, derivative thermogravimetry, and oxidative stability tests. Results indicated β-CDCHOM and PSCHOM had significantly higher EE values (80.40% and 75.52%) than MDCHOM and HP-β-CDCHOM (39.36% and 48.32%). The particle sizes of the two microcapsules selected were both widely distributed with their spans being more than 1 µm and a certain degree of polydispersity. Microstructural and chemical characterizations indicated that β-CDCHOM had comparatively stable structure and good thermal stability compared with PSCHOM. Storage performances under light, oxygen, and temperature showed that β-CDCHOM was superior to PSCHOM, especially in terms of thermal and oxidative stability. This study demonstrates that β-CD embedding can be applied to improve the oxidative stability of vegetable oils such as hickory oil and act as a means of preparing functional supplementary material.

Plain set and stirred yogurt with different additives: implementation of food safety system as quality checkpoints

Hazard Analysis Critical Control Point (HACCP) is a risk management protocol developed to ensure food safety through a precautionary approach that is believed to offer assurances in producing safe food for customers. Yogurt is made in a number of phases, commencing with the collection of raw milk and ending with consumer consumption. While this is happening, major economic and health issues might arise from exposing the manufacturing line to biological, chemical, and/or physical contaminations. As a result, the decision tree approach was used to determine the CCPs during the production of yogurt. Additionally, biological dangers are incorporated as a by-product of the system's implementation performance. In particular, the plain set and nut puree-honey-fortified stirred yogurt manufacturing techniques are highlighted for the first time in this study. The potential manufacturing risks are described for the first time, together with information on how HACCP plans may guard against major risks that could result in the production of yogurt that is not in compliance with established standards.

Impact of different processing techniques on the key volatile profile, sensory, and consumer acceptance of black truffle (Tuber melanosporum Vittadini)

Fresh truffles which include black truffle (Tuber melanosporum Vittadini) deteriorate and lose aroma rapidly after harvest; therefore, postharvest processing via freeze-drying or encapsulation is an option to preserve truffle aroma for extended supply. However, the aroma profile that directly affects the truffle quality and consumer acceptance is influenced by processing and producers require processing options that balance processing feasibility with retention of a suitable aroma profile. This study aimed to determine the impact of freeze-drying and encapsulation on the profile of key volatiles, consumer discrimination, and overall sensory impression (aroma intensity, liking, and acceptability) of processed truffle products compared to the starting material (positive control). The study combined experimental-scale processing with GC-MS analysis and consumer sensory evaluation to compare and optimize postharvest processing options. Based on the results, some volatile changes were detected in the processed truffle products compared to the positive control which were aligned with the consumer discrimination (triangle test) and the aroma intensity score (consumer sensory test). Despite some chemical and sensory differences detected, the consumer panel did not have any preference for processed truffle products compared to the positive control. The overall finding indicates the potential value of processing truffles into a natural flavoring ingredient for food application via freeze-drying or encapsulation, which should be of great interest for the truffle and food industry. According to the correlation analysis, the consumer acceptance of a truffle product may be increased by retaining 1-octen-3-ol and methional, while reducing the amount of p-cresol in the product. PRACTICAL APPLICATION: The postharvest process of turning truffles into a food flavoring ingredient may cause undesirable volatile changes that would directly impact the aroma quality and consumer acceptance of the processed truffle products. Hence, the impacts of freeze-drying and encapsulation on the chemical and sensory profile of truffles were evaluated in this study. Overall, the results of the concurrent instrument and sensory analysis demonstrated that both freeze-drying and encapsulation are potential options for processing.

Inclusion of phenolic bioactives in high amylose corn starch for gastro-intestinal delivery

Starch is a staple food component with intricate architectures, some of which can be utilized as polysaccharidic delivery vehicles for bioactive compounds. This work describes the use of high amylose corn starch (HACS) to fabricate V-amylose inclusion complexes entrapping capsaicin or curcumin. In line with past studies, X-ray diffraction, differential scanning calorimetry, static laser scattering and scanning electron microscopy help affirm the formation of V6III-type complexes. Such HACS complexes entrap capsaicin and curcumin in structures with higher levels of crystallinity compared to HACS alone (14.61 ± 0.08%, 14.65 ± 0.08% vs. 10.24 ± 0.24%, respectively), high levels of encapsulation efficiency (88.77 ± 5.7% and 66.3 ± 0.99%, respectively) but without significant differences in colloid sizes between the various inclusion complexes (58.25 ± 1.34 μm or 58.98 ± 2.32 μm, respectively). In turn, in vitro gastro-intestinal digestion of HACS complexes with capsaicin or curcumin revealed both, phenolic bioactives significantly (p < 0.05) attenuated the intestinal breakdown of HACS. Interestingly, this attenuated HACS digestibility was accompanied by high gastric retention of the payloads and their sustained release during 2 h of exposure to intestinal conditions. Altogether, this work presents starch-based delivery systems that can entrap phenolic bioactives, release the payload in the intestine and possibly attenuate starch breakdown (because of its increased crystallinity). Thus, this work offers a platform for infusing foods with bioactive phenolics and stall the breakdown of starch.

Comparative evaluation of encapsulation using β-cyclodextrin versus freeze-drying for better retention and stabilizing of black Périgord truffle (Tuber melanosporum) aroma

This study aimed to develop a novel technique to retain and stabilize compounds contributing to truffle aroma by encapsulation using β-cyclodextrin. Two experiments were conducted. In the first experiment, the key volatile profile and microbial population of products resulting from three different encapsulation methods, namely direct mixing method (M1), direct mixing followed by ethanol addition method (M2), and paste method (M3), were compared with untreated truffles (positive control) over a 90-day period. The M2-derived product was the least optimal for retaining key volatile compounds despite showing the lowest microbial population. There was no significant difference in the volatile profile of products derived from M1 and M3 on day 0. However, it was observed that the M3-derived product could retain its volatile profile better than the M1-derived product by day 90. M3 was compared with freeze-drying in the second experiment. Freeze-dried truffles showed an overall higher relative percentage of volatiles than the M3-derived product on day 0. However, by day 90, some volatile changes occurred in the freeze-dried truffles but not in the M3-derived product. The findings indicate that while freeze-drying could adequately conserve truffle volatiles, the encapsulation of volatile compounds in β-cyclodextrin could improve the volatile stability of truffle products and allow for longer storage times. Microbes were found in all encapsulated truffle products and freeze-dried truffles on days 0 and 90, suggesting the need to explore the possibility of incorporating a decontamination step in the process prior to either encapsulation or freeze-drying. PRACTICAL APPLICATION: A technique to capture and stabilize compounds responsible for truffle aroma by encapsulation using β-cyclodextrin was developed and compared with freeze-drying in this study. The overall finding suggests that while freeze-drying of truffle could sufficiently preserve volatiles, encapsulating truffle volatiles with β-cyclodextrin may improve its stability, extending its shelf life, which can be applied in the development of a natural truffle ingredient that can be applied in food product development.

Impact of polysaccharide mixtures on the formation, stability and EGCG loading of water-in-oil high internal phase emulsions

Water-in-oil (W/O) high internal phase emulsions (HIPEs) were prepared using polyglycerol polyricinoleate (PGPR) and polysaccharide blends consisting of konjac glucomannan (KGM) and octenyl succinic anhydride starch (OSA-starch). The formation, stability, and functionality of these emulsions were varied by adjusting the ratio of KGM and OSA-starch. Interfacial tension measurements indicated that the OSA-starch co-adsorbed to the water-oil interface with PGPR, which would have led to the formation of a polysaccharide-layer that helped prevent separation of the HIPEs. The centrifugal stability, rheological and microstructural results indicated that the W/O HIPEs exhibited well pH, ionic and thermal stability. The encapsulation efficiency, stability, and bioaccessibility of the EGCG in the W/O HIPEs were evaluated by using EGCG as a model hydrophilic nutraceutical. This study provides useful insights into the utilization of emulsion technology to reduce the fat content and improve the nutritional profile of foods with oily continuous phases, such as spreads.

Encapsulation of Orange Oil Using Fluidized Bed Granulation

The primary objective of this research is to determine how granulation compares to spray drying/agglomeration for producing larger, more dense flavoring particles. Granulation can yield large, dense particles and thereby negate the need for a two-step process (spray drying followed by agglomeration) to achieve improved flow/handling properties of dry flavorings. In this study, a 55% solids slurry (blend of OSAn-modified starch and maltodextrin 15DE) was prepared and then single-fold orange peel oil was added at 20 or 25% of the carrier solids level. The 20% flavoring emulsion was spray dried (SD), and a portion of the resultant powder then agglomerated (Agg) in a bottom spray, fluidized bed. A second emulsion of the same carrier composition but using 25% orange oil based on carrier solids was prepared and subjected to fluidized bed granulation (FBG). Particle size, density, orange oil retention and oxidative stability on storage were determined. Overall, it is observed during this study that FBG produces orange oil encapsulates that possess better properties, such as more resistance to oxidation, a better retention of orange oil and a higher density than SD or SD/Agg powders.

Molecular insight into the interactions between starch and cuminaldehyde using relaxation and 2D solid-state NMR spectroscopy

The interaction between cuminaldehyde and starch mainly governed the effect of further handling on food applications of cuminaldehyde. However, little information is available about the interactions of these components. We utilized relaxation and heteronuclear correlation (HETCOR) solid-state NMR spectroscopy to investigate the interaction between cuminaldehyde and porous starch at molecular level. We found that the interactions occurred mainly through hydrogen bonds. Cuminaldehyde molecules were restricted by starch, which resulted in the limitation of their movements and the longer ¹H T₁ relaxation time. Furthermore, the well resolved correlated peaks in 2D ¹H-¹³C HETCOR spectrum confirmed the formation of hydrogen bonds. The oxygen atoms at hydroxyl-2,3 of starch were the binding sites, which combined with hydrogens of cuminaldehyde. This present work not only afford a new approach to obtain a molecular understanding of interactions, but also expanded the application of solid-state NMR to investigation of the interaction on functional components.

Contribution of starch to the flavor of rice-based instant foods

Increased consumption of instant foods has led to research attention, especially rice-based instant foods. Starch, one of the most important components of rice, significantly affects food quality. However, the mechanisms by which starch contributes to rice-based instant foods flavor are poorly understood in many cases. The review aims to describe the common mechanisms by which starch contributes to food flavor, including participating in flavor formation, and affecting flavor release throughout starch multiscale structure: particle morphology, crystal structure, molecular structure. Five specific examples of rice-based instant foods were further analyzed to summarize the specific contribution of starch to flavor, including instant rice, fermented rice cake, rice noodles, fried rice, and rice dumplings. During foods processing, reducing sugars produced by heating or enzymatic hydrolysis of starch participate in Maillard reaction, caramelization and thermal degradation, which directly or indirectly affect the formation of flavor compounds. In addition, adsorption by granules, encapsulation by retrograded V-type crystal, and controlled release by starch gel all contribute to rice-based instant food flavor qualities. These mechanisms jointly contribute to flavor compounds formation and release. Proper theoretical application and improved processing methods are needed to promote the high-quality, mechanization, and automation of rice-based instant foods production.

Isolation, modification, and characterization of rice starch with emphasis on functional properties and industrial application: a review

Starch is one of the organic compounds after cellulose found most abundantly in nature. Starch significantly varies in their different properties like physical, chemical, thermal, morphological and functional. Therefore, starch is modified to increase the beneficial characteristics and remove the shortcomings issues of native starches. The modification methods can change the extremely flexible polymer of starch with their modified physical and chemical properties. These altered structural attributes are of great technological values which have a wide industrial potential in food and non-food. Among them, the production of novel starches is mainly one that evolves with new value-added and functional properties is on high industrial demands. This paper provides an overview of the rice starch components and their effect on the technological and physicochemical properties of obtained starch. Besides, the tuned techno-functional properties of the modified starches through chemical modification means are highlighted.HighlightsNative and modified starches varies largely in physicochemical and functional traits.Modified physical and chemical properties of starch can change the extremely flexible polymer of starch.Techno-functional properties of the modified starches through chemical modification means are highlighted.Dual modification improves the starch functionality and increases the industrial applications.Production of novel starches is on high industrial demands because it mainly evolves with new value added and functional properties.

Preparation and characterization of octenyl succinylated starch microgels via a water-in-oil (W/O) inverse microemulsion process for loading and releasing epigallocatechin gallate

Corn starch (CS), octenyl succinic anhydride modified corn starch (OSCS) and shells (OSC_s) microgels have been prepared using water-in-oil (W/O) inverse microemulsions for loading and releasing of epigallocatechin gallate (EGCG). The structural and morphological properties of CS, OSCS, and OSC_s microgels were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Transmission electron microscopy (TEM), and Thermogravimetric analysis (TGA). The strong hydrogen bonds between starch molecules in the W/O system and interplay between hydroxyl groups of EGCG and oxygen atoms of starch microgels were formed. OSC_s microgel showed low average particle size and weak thermal stability with an irregular shape and a typical V-type crystalline structure. Encapsulation efficiency (EE) and clearance rate of 2,2-diphenyl-1-picrylhydrazyl (DPPH) for EGCG were ranged between 41.78 and 63.89% and 75.53-85.37%, respectively, when absorbed into OSCS and OSC_s microgels, the values which were higher than that of CS microgel. Further, OS starch microgels (particularly OSC_s) modulated the slow release of EGCG into simulated gastrointestinal tract conditions and therefore could be proposed as an encapsulating agent for loading polyphenols.

Spray Drying for the Encapsulation of Oils-A Review

The application of the spray drying technique in the food industry for the production of a broad range of ingredients has become highly desirable compared to other drying techniques. Recently, the spray drying technique has been applied extensively for the production of functional foods, pharmaceuticals and nutraceuticals. Encapsulation using spray drying is highly preferred due to economic advantages compared to other encapsulation methods. Encapsulation of oils using the spray drying technique is carried out in order to enhance the handling properties of the products and to improve oxidation stability by protecting the bioactive compounds. Encapsulation of oils involves several parameters-including inlet and outlet temperatures, total solids, and the type of wall materials-that significantly affect the quality of final product. Therefore, this review highlights the application and optimization of the spray drying process for the encapsulation of oils used as food ingredients.

Vitamin C stability in acerola and camu-camu powder obtained by spray drying

Abstract Acerola and camu-camu fruits possess high vitamin C content. However, since these fruits are little consumed in their fresh form, it is important to consider that vitamin C can be oxidized depending on storage conditions. Thus, this study aimed to produce acerola and camu-camu powders by spray drying to maintain the stability of their vitamin C content during storage. Acerola and camu-camu powders were characterized in relation to their physicochemical characteristics, antioxidant activity, and vitamin C concentration and stability under different storage conditions (30 °C and 40 °C, 75% relative humidity). In general, the powders were proven to be stable, with low water activity (< 0.40) and humidity (< 4.0 g/100 g powder), as well as high vitamin C concentrations (1593.2 and 6690.4 mg/100 g of powder for acerola and camu-camu, respectively). Furthermore, we observed a high antioxidant activity by ABTS●+, DPPH• and FRAP assays. The powders stored at lower temperature (30 °C) showed higher vitamin C stability. In conclusion, acerola and camu-camu powders produced by spray drying are potential sources of vitamin C and active compounds and are therefore suitable for several food industry applications.

Structural Characterization and Digestibility of Curcumin Loaded Octenyl Succinic Nanoparticles

Curcumin displays anti-cancer, anti-inflammatory and anti-obesity properties but its water insolubility limits the wholesome utility. In this study, curcumin has been encapsulated in an amphiphilic biopolymer to enhance its water solubility. This was accomplished through self-assembly of octenyl succinic anhydride-short glucan chains (OSA-SGC) and curcumin. The nanoparticles were prepared with the degree of substitution (DS) of 0.112, 0.286 and 0.342 of OSA. Thus prepared nanoparticles were in the range of 150-200 nm and display high encapsulation efficiency and high loading capacity of curcumin. The Fourier-transform infrared (FTIR) and X-ray diffraction analyses confirmed the curcumin loading in the OSA-SGC nanoparticles. The complexes possessed a V-type starch structure. The thermo gravimetric analysis (TGA) revealed the thermal stability of encapsulated curcumin. The OSA-SGC nanoparticles greatly improved the curcumin release and dissolution, and in-turn promoted the sustained release.

The effect of cyclodextrin complexation on the solubility and photostability of nerolidol as pure compound and as main constituent of cabreuva essential oil

Nerolidol (Ner), a major component of many plant essential oils, is known for its various biological properties. However, the low solubility of Ner in water and its susceptibility to degradation limit its application. The aim of our study was to improve the solubility and photostability of Ner through its encapsulation in different cyclodextrins (CDs). The formation constants of cis-, trans-Ner and their commercial mixture with various CDs (α-CD, β-CD, γ-CD, HP-β-CD, RAMEB, CRYSMEB and SBE-β-CD) were determined by phase solubility studies and confirmed by the spectral displacement UV-visible method. The solubility of cabreuva essential oil (EO) rich in trans-Ner was also evaluated by total organic carbon (TOC) analysis. The encapsulation efficiency (EE %) of Ner in HP-β-CD solid complexes was assessed by HPLC. The structural characterization of CD/trans-Ner inclusion complex was then conducted by NMR spectroscopy followed by molecular modelling studies. The effect of encapsulation on the Ner photostability was also carried out over time under UVB irradiation. A_L-type phase-solubility diagrams were obtained, suggesting the formation of 1:1 CD/Ner inclusion complexes. The solubility of Ner was enhanced by approximately 70-fold in the presence of 10 mM HP-β-CD. Moreover, high EE % values were obtained for 5:1 and 10:1 HP-β-CD:Ner molar ratios. NMR and molecular modelling studies revealed the most stable structure for trans-Ner inside the CD cavity with the OH group oriented towards the wider rim of the CD. Finally, CD encapsulation of Ner as pure compound or as main component of the cabreuva EO, protected it from degradation. This effect was more pronounced as the concentration of CD increased. These findings suggested that CDs are promising encapsulating carriers for Ner by enhancing its solubility and stability and thereby its application in food industry.