Effects of high hydrostatic pressure (HHP) on the protein structure and thermal stability of Sauvignon blanc wine

High-pressure microfluidization enhanced the stability of sodium caseinate-EGCG complex-stabilized fish oil emulsion

Improving the emulsion-stabilizing effect of protein by chemical or physical modification has been paid much attention recently. Here, sodium caseinate (CS) was treated by high-pressure-microfluidization (HPM) under 0-100 MPa, and was further complexed with (-)-epigallocatechin-3-gallate (EGCG) to form an excellent emulsifier that stabilized fish oil emulsions. Results showed that HPM treatment (especially 80 MPa) significantly changed the secondary structure of CS, and 80 MPa-PCS-EGCG had the best emulsifying and antioxidant activities. In addition, after HPM treatment and EGCG bonding, CS formed a thicker interface layer on the surface of oil droplets, which could better protect the fish oil from the influence by oxygen, temperature and ion concentration. Moreover, the fish oil emulsion stabilized by PCS-EGCG complex significantly delayed the release of free fatty acids subjected to in vitro digestion. Conclusively, HPM-treated CS-EGCG complex could be a potential emulsifier to improve the stability of fish oil emulsions.

Chemically Modified Clay Adsorbents Used in the Retention of Protein and Polyphenolic Compounds from Sauvignon Blanc White Wine

During the manufacturing process of white wine, various physicochemical reactions can occur and can affect the quality of the finished product. For this reason, it is necessary to apply different treatments to minimize distinct factors such as protein instability and pinking phenomenon, which can affect the organoleptic properties of wines and their structure. In this work, a new method for the preparation of a sorbent-type material is presented through the fractional purification of native bentonite in three fractions (Na-BtF1, Na-BtF2, and Na-BtF3). Furthermore, the influence of the prepared sorbents on pH, conductivity, and amino nitrogen level was analyzed. The absorbents prepared and tested in wine solutions were characterized using the following physico-chemical methods: Brunauer-Emmett-Teller and Barrett-Joyner-Halenda (BET-BJH) method, X-ray diffraction (XRD) technique, and transform-coupled infrared spectroscopy Fourier with attenuated total reflection (FTIR-ATR). Following the analyses carried out on the retention of protein content and polyphenolic compounds, it was found that materials based on natural clay have suitable adsorption properties.

Study on potential antigenicity and functional properties of whey protein treated by high hydrostatic pressure based on structural analysis

High hydrostatic pressure (HHP) is extensively utilized in the field of food processing due to its remarkable ability to preserve the freshness of food. The potential antigenicity of β-lactoglobulin (β-LG) in whey protein isolate (WPI, 3%) treated by HHP was detected by enzyme linked immunosorbent assay (ELISA) using monoclonal antibodies. Furthermore, the impact of pressure-induced structural alterations on the emulsification properties and antioxidant activity of WPI was investigated. The findings revealed that pressures exceeding 300 MPa resulted in molecular aggregation, the formation of inter-molecular disulfide bonds, and an increase in surface hydrophobicity (H0). The percentage of β-sheet decreased along with the pressure. The results showed the increment of α-helix and β-turn with pressure. ELISA demonstrated a significant reduction in the antigenicity of β-LG following HHP treatment (100-600 MPa), with a slight recovery observed at 300 MPa. These spatial structural modifications led to the unfolding of the β-LG molecule, thereby enhancing its digestibility. Moreover, HHP treatment substantially improved the antioxidant properties, with the exposure to hydrophobic amino acids contributing to increased antioxidant properties and emulsion stability.

Food Peptides for the Nutricosmetic Industry

In recent years, numerous reports have described bioactive peptides (biopeptides)/hydrolysates produced from various food sources. Biopeptides are considered interesting for industrial application since they show numerous functional properties (e.g., anti-aging, antioxidant, anti-inflammatory, and antimicrobial properties) and technological properties (e.g., solubility, emulsifying, and foaming). Moreover, they have fewer side effects than synthetic drugs. Nevertheless, some challenges must be overcome before their administration via the oral route. The gastric, pancreatic, and small intestinal enzymes and acidic stomach conditions can affect their bioavailability and the levels that can reach the site of action. Some delivery systems have been studied to avoid these problems (e.g., microemulsions, liposomes, solid lipid particles). This paper summarizes the results of studies conducted on biopeptides isolated from plants, marine organisms, animals, and biowaste by-products, discusses their potential application in the nutricosmetic industry, and considers potential delivery systems that could maintain their bioactivity. Our results show that food peptides are environmentally sustainable products that can be used as antioxidant, antimicrobial, anti-aging, and anti-inflammatory agents in nutricosmetic formulations. Biopeptide production from biowaste requires expertise in analytical procedures and good manufacturing practice. It is hoped that new analytical procedures can be developed to simplify large-scale production and that the authorities adopt and regulate use of appropriate testing standards to guarantee the population's safety.

Effects of soybean oil on rheological characteristics of dough under high hydrostatic pressure

In order to improve the stability of dough with soybean oil, this paper explored the effect of soybean oil addition on the rheological characteristics of dough under high hydrostatic pressure. The results showed that, compared with the dough without soybean oil, the β-sheet, disulfide bonds content and gauche-ganche-ganche in the dough increased by 4.23%, 0.85 μmol/g and 4.16% respectively when the dough was added with 6% soybean oil, which improved the degree of cross-linking polymerization of gluten protein and the stability of gluten network. Meanwhile, the dough had the highest elastic modulus and the lowest maximum creep compliance (6.85 Pa^-1 ×10^-4 ), indicating that 6% soybean oil significantly increased the elasticity and hardness of the dough. The results of short-range ordered structure and paste properties showed that with the addition of soybean oil, the ordered structure and paste viscosity decreased with the increase of soybean oil.

Protein Hydrolysis by Subcritical Water: A New Perspective on Obtaining Bioactive Peptides

The importance of bioactive peptides lies in their diverse applications in the pharmaceutical and food industries. In addition, they have been projected as allies in the control and prevention of certain diseases due to their associated antioxidant, antihypertensive, or hypoglycemic activities, just to mention a few. Obtaining these peptides has been performed traditionally by fermentation processes or enzymatic hydrolysis. In recent years, the use of supercritical fluid technology, specifically subcritical water (SW), has been positioned as an efficient and sustainable alternative to obtain peptides from various protein sources. This review presents and discusses updated research reports on the use of subcritical water to obtain bioactive peptides, its hydrolysis mechanism, and the experimental designs used for the study of effects from factors involved in the hydrolysis process. The aim was to promote obtaining peptides by green technology and to clarify perspectives that still need to be explored in the use of subcritical water in protein hydrolysis.

Influence of iron binding in the structural stability and cellular internalization of bovine lactoferrin

Lactoferrin (Lf) is an iron-binding glycoprotein and a component of many external secretions with a wide diversity of functions. Structural studies are important to understand the mechanisms employed by Lf to exert so varied functions. Here, we used guanidine hydrochloride and high hydrostatic pressure to cause perturbations in the structure of bovine Lf (bLf) in apo and holo (unsaturated and iron-saturated, respectively) forms, and analyzed conformational changes by intrinsic and extrinsic fluorescence spectroscopy. Our results showed that the iron binding promotes changes on tertiary structure of bLf and increases its structural stability. In addition, we evaluated the effects of bLf structural change on the kinetics of bLf internalization in Vero cells by confocal fluorescence microscopy, and observed that the holo form was faster than the apo form. This finding may indicate that structural changes promoted by iron binding may play a key role in the intracellular traffic of bLf. Altogether, our data improve the comprehension of bLf stability and uptake, adding knowledge to its potential use as a biopharmaceutical.

Emergent Proteins-Based Structures-Prospects towards Sustainable Nutrition and Functionality

The increased pressure over soils imposed by the need for agricultural expansion and food production requires development of sustainable and smart strategies for the efficient use of resources and food nutrients. In accordance with worldwide transformative polices, it is crucial to design sustainable systems for food production aimed at reducing environmental impact, contributing to biodiversity preservation, and leveraging a bioeconomy that supports circular byproduct management. Research on the use of emergent protein sources to develop value-added foods and biomaterials is in its infancy. This review intends to summarize recent research dealing with technological functionality of underused protein fractions, recovered from microbial biomass and food waste sources, addressing their potential applications but also bottlenecks. Protein-based materials from dairy byproducts and microalgae biomass gather promising prospects of use related to their techno-functional properties. However, a balance between yield and functionality is needed to turn this approach profitable on an industrial scale basis. In this context, downstream processing should be strategically used and properly integrated. Food solutions based on microbial proteins will expand in forthcoming years, bringing the opportunity to finetune development of novel protein-based biomaterials.

Citric acid promotes disulfide bond formation of whey protein isolate in non-acidic aqueous system

Impacts of citric acid (CA) treatment under non-acidic conditions (pH 7.0, 8.0 and 9.0) on whey protein isolate (WPI) were examined in this study. Size exclusion chromatography and SDS-PAGE indicated that molecular size and weight of WPI-CA became larger at pH 7.0, 8.0 and 9.0 with CA ranged from 0 to 15 mg/mL, but the protein aggregates disappeared after β-mercaptoethanol was added. The free SH groups of WPI-CA gradually decreased. This could be deduced that CA could promote disulfide bond formation of WPI at the non-acidic pH values. Furthermore, fourier transform infra-red (FTIR) spectroscopy and fluorescence spectroscopy data confirmed the conformational changes of secondary and tertiary structures of CA-modified WPI, respectively. Therefore, these results suggested that disulfide bond formation of WPI occurred at citric acid treatment under non-acidic conditions, being contributed to production of its larger molecular size substances and alteration of its structural characteristics.

Functionality of Food Components and Emerging Technologies

This review article introduces nutrition and functional food ingredients, explaining the widely cited terms of bioactivity, bioaccessibility, and bioavailability. The factors affecting these critical properties of food components are analyzed together with their interaction and preservation during processing. Ultimately, the effect of emerging (non-thermal) technologies on different food components (proteins, carbohydrates, lipids, minerals, vitamins, polyphenols, glucosinolates, polyphenols, aroma compounds, and enzymes) is discussed in spite of preserving their functional properties. Non-thermal technologies can maintain the bioavailability of food components, improve their functional and technological properties, and increase the recovery yields from agricultural products. However, the optimization of operational parameters is vital to avoid degradation of macromolecules and the oxidation of labile compounds.

Green technologies for the extraction of proteins from jackfruit leaves (Artocarpus heterophyllus Lam)

The application of emerging technologies such as ultrasound, microwaves and high hydrostatic pressure, allows the extraction of compounds in a sustainable manner from a vegetable matrix with a high value such as jackfruit leaf proteins (Artocarpus heterophyllus Lam). Currently, the main method of protein extraction is based on the precipitation with the use of an aggressive solvent, therefore it is necessary to optimize extraction methods with a minimum waste production. In the protein extraction of jackfruit leaves, we obtained a content of 84.1 mg/g using solvents. On the other hand, emergent extractions such as ultrasound, microwaves, and high hydrostatic pressure showed concentrations of 96.3, 95.6 and 147.3 mg/g, respectively. In addition, we found that the best extraction agent was 0.5 M NaCl, offering a range of possibilities that support green technologies as an imperative change in the food industry.

Use of UHPH to Obtain Juices With Better Nutritional Quality and Healthier Wines With Low Levels of SO2

Ultra-high pressure homogenization (UHPH) is a high pressure technique in which a fluid is pressurized by pumping at higher than 200 MPa and instantaneously depressurized at atmospheric pressure across a special valve. The full process takes <0.2 s and the in-valve time is <0.02 s. In the valve, extremely intense impacts and shear forces produce the nanofragmentation of biological tissue at a range of 100-300 nm. The antimicrobial effect is highly effective, reaching easily inactivation levels higher than 6-log cycles even at low in-valve temperatures. At in-valve temperatures of 140-150°C (0.02 s) the destruction of thermoresistant spores is possible. Even when the temperature in-valve can be elevated (70-150°C), it can be considered a gentle technology because of the tremendously short processing time. It is easy to get outlet temperatures after valve of 20-25°C by the expansion and assisted by heat exchangers. Thermal markers as hydroxymethylfurfural (HMF) are not formed, nor are deleterious effects observed in sensitive compounds as terpenes or anthocyanins, probably because of the low effect in covalent bonds of small molecules of the high-pressure techniques compared with thermal technologies. Additionally, intense inactivation of oxidative enzymes is observed, therefore protecting the sensory and nutritional quality of fruit juices and avoiding or reducing the use of antioxidants as sulphites. UHPH can be consider a powerful and highly effective continuous and sterilizing technology without thermal repercussions, able to keep fresh juices with most of their initial sensory and nutritional quality and allowing high-quality and natural fermented derivatives as wine.

White Wine Protein Instability: Mechanism, Quality Control and Technological Alternatives for Wine Stabilisation—An Overview

Wine protein instability depends on several factors, but wine grape proteins are the main haze factors, being mainly caused by pathogenesis-related proteins (thaumatin-like proteins and chitinases) with a molecular weight between 10~40 kDa and an isoelectric point below six. Wine protein stability tests are needed for the routine control of this wine instability, and to select the best technological approach to remove the unstable proteins. The heat test is the most used, with good correlation with the natural proteins’ precipitations and because high temperatures are the main protein instability factor after wine bottling. Many products and technological solutions have been studied in recent years; however, sodium bentonite is still the most efficient and used treatment to remove unstable proteins from white wines. This overview resumes and discusses the different aspects involved in wine protein instability, from the wine protein instability mechanisms, the protein stability tests used, and technological alternatives available to stabilise wines with protein instability problems.

Storage Temperature Impacts on Anthocyanins Degradation, Color Changes and Haze Development in Juice of "Merlot" and "Ruby" Grapes (Vitis vinifera)

This study evaluated the degradation kinetics of selected anthocyanins and the change in polymeric color, browning index, and haze development of grape juices from “Merlot” and “Ruby” grape cultivars stored at 5, 25, and 35°C for up to 360 days. Five major anthocyanins namely malvidin-3-O-glucoside (M3G), delphinidin-3-O-glucoside (D3G), petunidin-3-O-glucoside (Pt3G), peonidin-3-O-glucoside (Pn3G), and cyanidin-3-O-glucoside (C3G) were identified. Juice from “Merlot” had significantly higher (p < 0.05) content of all individual anthocyanins as compared to “Ruby.” During the long-term storage, total, and individual anthocyanins from both cultivars degraded following first-order reaction kinetics at the rate strongly dependent on temperature. At the end of the storage, noticeably higher loss of anthocyanins (95–99.9%) was observed at 25 and 35°C as compared to storage at 5°C [50–60% (“Merlot”); 74–81% (“Ruby”)]. Considerably lower rate of decay was observed at 5°C (k = 0.01–0.04) as compared to 25 (k = 0.04–0.14) and 35°C (k = 0.05–0.14) storage temperatures. The most temperature sensitive anthocyanin compounds were C3G (E_a = 66.5 kJ/mol) and D3G (E_a = 63.3 kJ/mol). At higher storage temperatures, significant (p < 0.05) and strong negative correlations were observed between anthocyanin concentrations and the levels of haze, polymeric and brown color development during storage. Storing grape juice, at lower temperature conditions could reduce the continuous loss of biologically active anthocyanins as well as the development of haze and brown color.

High-Pressure Homogenization Pretreatment before Enzymolysis of Soy Protein Isolate: the Effect of Pressure Level on Aggregation and Structural Conformations of the Protein

The high-pressure homogenization (HPH) treatment of soybean protein isolate (SPI) before enzymatic hydrolysis using bromelain was investigated. Homogenization pressure and cycle effects were evaluated on the enzymatic degree of hydrolysis and the antioxidant activity of the hydrolysates generated. The antioxidant activity of SPI hydrolysates was analyzed by 1,1-dipheny-2-picrylhydrazyl (DPPH). The sizes and structures of the SPI-soluble aggregate after HPH treatment were analyzed using dynamic and static laser light scattering. The changes in the secondary structure, as measured by Fourier transform infrared spectroscopy (FTIR) and the macromorphology of SPI, were measured by scanning electron microscope (SEM). These results suggested that the HPH treatment (66.65%) could increase the antioxidant activities of the SPI hydrolysates compared with the control (54.18%). SPI hydrolysates treated at 20 MPa for four cycles obtained higher DPPH radical-scavenging activity than other samples. The control was predicted to be a hard sphere, and SPI treatment at 10 MPa was speculated to be Gaussian coil, polydisperse, and then the high-pressure treated SPI became a hollow sphere. Changes in the secondary structures showed protein aggregate formation and rearrangements. The image of SPI varied from a globular to a clump structure, as observed by the SEM. In conclusion, combining HPH treatment and enzymolysis could be an effective way to improve the antioxidant activity of the SPI.

Application of differential scanning calorimetry to estimate quality and nutritional properties of food products

Over the past years, both food researchers and food industry have shown an increased interest in finding techniques that can estimate modifications in quality, nutritional, and thermophysical properties of food products during processing and/or storage. For instance, differential scanning calorimetry (DSC) has attracted the interest of scientific community because only a small amount of sample is needed for analysis. Moreover, it does not require any specific sample preparation, and is a repeatable and reliable method. In addition, DSC methodology needs a short time for experiments compared with other techniques used for the same purpose. At this stage of investigation, there is a need to evaluate the commonly accepted and new emerging DSC applications to establish the optimum conditions of emerging processing. This paper reviews the current and new insights of DSC technique for the estimation of quality, nutritional, and thermophysical properties of food products during conventional and emerging processing and/or subsequent storage. The estimation of different properties in several food matrices after processing and/or storage is also discussed.

Is caffeic acid, as the major metabolite present in Moscatel wine protein haze hydrolysate, involved in protein haze formation?

This work was conducted to identify the major low molecular weight compounds present in the wine precipitate and to assess their potential contribution to wine protein haze formation. The heat-induced protein precipitate from a white Moscatel of Alexandria wine was subjected to alkaline hydrolysis. The major compound present was found to be caffeic acid among other minor, unidentified compounds. Caffeic acid was identified by both UV-vis and ¹H NMR spectra. The concentration of caffeic acid in the original wine sample was 1.1mg/L, as quantified by HPLC following SPE. Heat stability tests were performed using two different concentrations of caffeic acid and its ester caftaric acid in model wine solution added of isolated wine protein. No correlation was found between caffeic or caftaric acid concentration and haze forming potential in wine model solution. This work shows that caffeic acid is present in considerable amounts in Moscatel wine protein haze, but does not seem to trigger or participate in the protein aggregation mechanism upon heating.

Influence of High Hydrostatic Pressure Technology on Wine Chemical and Sensorial Characteristics: Potentialities and Drawbacks

During last years, scientific research on high hydrostatic pressure (HHP) as a nonthermal processing technology for preservation or aging of wine has increased substantially. HHP between 200 and 500MPa is able to inactivate bacteria and yeasts in red and white wines, suggesting that it may be used for wine preservation. However, these treatments have been shown to promote changes on sensorial and physicochemical characteristics in both red and white wines, not immediately in the first month, but along storage. The changes are observed in wine color, aroma, and taste due mainly to reactions of phenolic compounds, sugars, and proteins. These reactions have been associated with those observed during wine aging, leading to aged-like wine characteristics perceived by sensorial analysis. This chapter will present the influence of HHP technology on wine chemical and sensorial characteristics, criticaly discussing its potentialities and drawbacks. The appropriate use of HHP, based on the scientific knowledge of the reactions occuring in wine promoted by HHP, will allow to exploit this technology for wine production achieving distinct characteristics to address particular market and consumer demands.

High Hydrostatic Pressure (HHP)-Induced Structural Modification of Patatin and Its Antioxidant Activities

Patatin represents a group of homologous primary storage proteins (with molecular weights ranging from 40 kDa to 45 kDa) found in Solanum tuberosum L. This group comprises 40% of the total soluble proteins in potato tubers. Here, patatin (40 kDa) was extracted from potato fruit juice using ammonium sulfate precipitation (ASP) and exposed to high hydrostatic pressure (HHP) treatment (250, 350, 450, and 550 MPa). We investigated the effect of HHP treatment on the structure, composition, heat profile, and antioxidant potential, observing prominent changes in HHP-induced patatin secondary structure as compared with native patatin (NP). Additionally, significant (p < 0.05) increases in β-sheet content along with decreases in α-helix content were observed following HHP treatment. Thermal changes observed by differential scanning calorimetry (DSC) also showed a similar trend following HHP treatment; however, the enthalpy of patatin was also negatively affected by pressurization, and free sulfhydryl content and surface hydrophobicity significantly increased with pressurization up to 450 MPa, although both interactions progressively decreased at 550 MPa. The observed physicochemical changes suggested conformational modifications in patatin induced by HHP treatment. Moreover, our results indicated marked enhancement of antioxidant potential, as well as iron chelation activities, in HHP-treated patatin as compared with NP. These results suggested that HHP treatment offers an effective and green process for inducing structural modifications and improving patatin functionality.

Oenological and Quality Characteristic on Young White Wines (Sauvignon Blanc): Effects of High Hydrostatic Pressure Processing

High hydrostatic pressure (HHP) has shown to have an effect of enhancing some properties without detrimental effects on important quality characteristics, such as colour, pH, and turbidity. This suggests that this technique can be used as an alternative to the existing methods used in wine industry processing. The aim of this study was to investigate the effects of HHP on aroma compounds and also sensory and quality properties of young white wine. HHP treatment did not influence physicochemical parameters, total phenols, and flavonoid contents of white wine; however, the results from analysis of wine indicate that there was a great variation in the concentration of free and total sulphur dioxide (SO2) values and antioxidant capacity of white wine after HHP application. The sensory attributes, such as taste, odour, and overall quality, were not affected by HHP processing at 300 MPa. The chromatic characteristics changed slightly after applying HHP, but these changes could not be visually perceived because they were less than 5%. The use of this technique has the potential to decrease the amount of SO2 added to raw grapes thus maintaining the same properties found in untreated wine. This study provided valuable insights into the biochemical and sensory composition of commercial white wine and how this might change during HHP processing.

Effect of high pressure treatment on the aging characteristics of Chinese liquor as evaluated by electronic nose and chemical analysis

Several high pressure (HP) treatments (100-400 MPa; 15 and 30 min) were applied to Chinese "Junchang" liquor, and aging characteristics of the liquor were evaluated. Results from the principal component analysis and the discriminant factor analysis of E-Nose demonstrated that HP treatment at 300 and 400 MPa resulted in significant (p < 0.05) changes in aroma components of the liquor. An increase in total ester content and a decrease in total acid content were observed for all treated samples (p < 0.05), which was verified by gas chromatography analysis. In addition, a slight decrease in alcohol content was found for HP treatment at 400 MPa for 30 min. These changes and trends were in accordance with the natural aging process of Chinese liquor. However, HP treatment caused a slight increase in solid content, which might be somewhat undesirable. Sensory evaluation results confirmed that favorable changes in color and flavor of Chinese liquor were induced by HP treatment; however, overall gaps still existed between the quality of treated and six-year aged samples. HP treatment demonstrated a potential to accelerate the natural aging process for Chinese liquor, but long term studies may be needed further to realize the full potential.

Enzymatic hydrolysis of anchovy fine powder at high and ambient pressure, and characterization of the hydrolyzates

BACKGROUND

At specific conditions of high pressure, the stability and activity of some enzymes are reportedly known to increase. The aim of this study was to apply pressure-tolerant proteases to hydrolyzing anchovy fine powder (AFP) and to determine product characteristics of the resultant hydrolyzates.

RESULTS

Anchovy fine powder enzyme hydrolyzates (AFPEHs) were produced at 300 MPa and ambient pressure using combinations of Flavourzyme 500MG, Alcalase 2.4L, Marugoto E and Protamex. When the same protease combination was used for hydrolysis, the contents of total soluble solids, total water-soluble nitrogen and trichloroacetic acid-soluble nitrogen in the AFPEHs produced at 300 MPa were conspicuously higher than those in the AFPEHs produced at ambient pressure. This result and electrophoretic characteristics indicated that the high-pressure process of this study accelerates protein hydrolysis compared with the ambient-pressure counterpart. Most peptides in the hydrolyzates obtained at 300 MPa had molecular masses less than 5 kDa. Functionality, sensory characteristics and the content of total free amino acids of selected hydrolyzates were also determined.

CONCLUSION

The high-pressure hydrolytic process utilizing pressure-tolerant proteases was found to be an efficient method for producing protein hydrolyzates with good product characteristics.

High Pressure Treatment in Foods

High hydrostatic pressure (HHP), a non-thermal technology, which typically uses water as a pressure transfer medium, is characterized by a minimal impact on food characteristics (sensory, nutritional, and functional). Today, this technology, present in many food companies, can effectively inactivate bacterial cells and many enzymes. All this makes HHP very attractive, with very good acceptance by consumers, who value the organoleptic characteristics of products processed by this non-thermal food preservation technology because they associate these products with fresh-like. On the other hand, this technology reduces the need for non-natural synthetic additives of low consumer acceptance.