Value-added Ingredients Research Articles

Metabolomics of Chlorophylls and Carotenoids: Analytical Methods and Metabolome-Based Studies.

Chlorophylls and carotenoids are two families of antioxidants present in daily ingested foods, whose recognition as added-value ingredients runs in parallel with the increasing number of demonstrated functional properties. Both groups include a complex and vast number of compounds, and extraction and analysis methods evolved recently to a modern protocol. New methodologies are more potent, precise, and accurate, but their application requires a better understanding of the technical and biological context. Therefore, the present review compiles the basic knowledge and recent advances of the metabolomics of chlorophylls and carotenoids, including the interrelation with the primary metabolism. The study includes material preparation and extraction protocols, the instrumental techniques for the acquisition of spectroscopic and spectrometric properties, the workflows and software tools for data pre-processing and analysis, and the application of mass spectrometry to pigment metabolomics. In addition, the review encompasses a critical description of studies where metabolomics analyses of chlorophylls and carotenoids were developed as an approach to analyzing the effects of biotic and abiotic stressors on living organisms.

Identifying Potential Antioxidant Properties from the Viscera of Sea Snails (Turbo cornutus).

Turbo cornutus, the horned turban sea snail, is found along the intertidal and basaltic shorelines of Jeju Island, Korea. T. cornutus feeds on seaweeds (e.g., Undaria sp., and Ecklonia sp.) composed of diverse antioxidants. This study identified potential antioxidant properties from T. cornutus viscera tissues. Diverse extracts were evaluated for their hydrogen peroxide (H2O2) scavenging activities. T. cornutus viscera protamex-assisted extracts (TVP) were purified by gel filtration chromatography (GFC), and potential antioxidant properties were analyzed for their amino acid sequences and its peroxidase inhibition effects by in silico molecular docking and in vitro analysis. According to the results, T. cornutus viscera tissues are composed of many protein contents with each over 50%. Among the extracts, TVP possessed the highest H2O2 scavenging activity. In addition, TVP-GFC-3 significantly decreased intracellular reactive oxygen species (ROS) levels and increased cell viability in H2O2-treated HepG2 cells without cytotoxicity. TVP-GFC-3 comprises nine low molecular bioactive peptides (ELR, VGPQ, TDY, ALPHA, PAH, VDY, WSDK, VFSP, and FAPQY). Notably, the peptides dock to the active site of the myeloperoxidase (MPO), especially TDY and FAPQY showed the MPO inhibition effects with IC50 values of 646.0 ± 45.0 µM and 57.1 ± 17.7 µM, respectively. Altogether, our findings demonstrated that T. cornutus viscera have potential antioxidant properties that can be used as high value-added ingredients.

Phenolic Profile, Antioxidant Capacity and Antimicrobial Activity of Nettle Leaves Extracts Obtained by Advanced Extraction Techniques.

Nettle is a widely known plant whose high biological activity and beneficial medicinal effects are attributed to various bioactive compounds, among which polyphenols play an important role. In order to isolate polyphenols and preserve their properties, advanced extraction techniques have been applied to overcome the drawbacks of conventional ones. Therefore, microwave-assisted extraction (MAE) has been optimized for the isolation of nettle leaves polyphenols and it was compared to pressurized liquid extraction (PLE) and conventional heat-reflux extraction (CE). The obtained extracts were analyzed for their individual phenolic profile by UPLC MS2 and for their antioxidant capacity by ORAC assay. MAE proved to be the more specific technique for the isolation of individual phenolic compounds, while PLE produced extracts with higher amount of total phenols and higher antioxidant capacity. Both techniques were more effective compared to CE. PLE nettle extract showed antimicrobial activity against bacteria, especially against Gram-negative Pseudomonas fragi ATCC 4973 and Campylobacter jejuni NCTC 11168 strains. This suggests that PLE is suitable for obtaining a nettle extract with antioxidant and antimicrobial potential, which as such has great potential for use as a value-added ingredient in the food and pharmaceutical industry.

An integration study of microalgae bioactive retention: From microalgae biomass to microalgae bioactives nanoparticle

Microalgae metabolites include biologically active compounds with therapeutic effects such as anticancer, anti-inflammatory and immunomodulation effects. One of the most recent focuses is on utilizing microalgae lipid-based biologically active compounds in food applications. However, most microalgae biological active compounds in their natural forms have common drawbacks like low solubility, low physicochemical stability and strong susceptibility to degradation, which significantly limits their application in foods, therefore, it is important to find solutions to retain their functional properties. In the present work, a comprehensive review on multi-product biorefinery was carried out from upstream processing stage to downstream processing stage, and identify critical processes and factors that impact bioactive material acquisition and retention. Furthermore, since nanoencapsulation technology emerges as an effective solution for microalgae nutraceutical product's retention, this work also focus on the nanoparticle perspective and comprehensively reviews the current nanoencapsulation solutions of the microalgae bioactive extract products. The aim is to depict advances in the formulations of microalage bioactive nanoparticles and provide a critical analysis of the reported nanoparticle formation. Overall, through the investigation of microalgae from biomass to bioactive nanoparticles, we aim to facilitate microalgae nutraceuticals incorporation as high value-added ingredients in more functional food that can improve human health.

Influence of low molecular weight surfactants on the stability of model infant formula emulsions based on hydrolyzed rice protein

The emulsifying properties of rice protein ingredients, and their behaviour in the presence of other non-protein emulsifiers, are essential to support food applications. The objective of this study was to investigate the influence of different low molecular weight surfactants (LMWS) on the stability of model infant formula emulsions (10 g protein L−1, 35 g soybean oil L−1, 50 g carbohydrate L−1) based on a rice protein hydrolyzate (RPH). Inclusion of CITREM and DATEM, at concentrations greater than 1 g L−1, gave emulsions with mean fat globule diameters (D[4,3]) less than 1 μm with good creaming stability, while lecithin was less effective across the concentration range tested (i.e., 1–3 g L−1). Coalescence of the control emulsion was observed upon both storage (10 d at 4 °C) and heat treatment (95 °C × 5 min). Increasing CITREM concentration increased storage and heat stability of the emulsions, while addition of CITREM at 2 g L−1 facilitated the formation of a very stable product. This study provides a first insight into the potential of hydrolyzed rice protein to be used as a value-added ingredient in the production of nutritional beverages such as infant formula emulsions, and the influence of LMWS on the stability of such products.

Impact of Processing Approach and Storage Time on Bioactive and Biological Properties of Rocket, Spinach and Watercress Byproducts.

The high nutritional value of vegetables is well recognized, but their short shelf life and seasonal nature result in massive losses and wastes. Vegetable’s byproducts are an opportunity to develop value-added ingredients, increasing food system efficiency and environmental sustainability. In the present work, pulps and powders of byproducts from rocket and spinach leaves and watercress were developed and stored for six months under freezing and vacuum conditions, respectively. After processing and storage, microbiological quality, bioactive compounds (polyphenols, carotenoids and tocopherols profiles), antioxidant capacity, and pulps viscosity were analyzed. Generally, the developed vegetable’s pulps and powders were considered microbiologically safe. Although some variations after processing and storage were verified, the antioxidant activity was preserved or improved. A rich phenolic composition was also registered and maintained. During freezing, the quantitative carotenoid profile was significantly improved (mainly in rocket and spinach), while after drying, there was a significant decrease. A positive effect was verified in the vitamin E level. Both processing and storage conditions resulted in products with relevant phenolics, carotenoids and tocopherol levels, contributing to the antioxidant activity registered. Thus, this study demonstrates the potential of vegetable byproducts valorization through developing these functional ingredients bringing economic and environmental value into the food chain.

Olive Mill Wastewater as Renewable Raw Materials to Generate High Added-Value Ingredients for Agro-Food Industries

Olive oil production represents an agro-industrial activity of vital economic importance for many Mediterranean countries. However, it is associated with the generation of a huge amount of by-products, both in solid and liquid forms, mainly constituted by olive mill wastewater, olive pomace, wood, leaves, and stones. Although for many years olive by-products have only been considered as a relevant environmental issue, in the last decades, numerous studies have deeply described their antioxidant, anti-inflammatory, immunomodulatory, analgesic, antimicrobial, antihypertensive, anticancer, anti-hyperglycemic activities. Therefore, the increasing interest in natural bioactive compounds represents a new challenge for olive mills. Studies have focused on optimizing methods to extract phenols from olive oil by-products for pharmaceutical or cosmetic applications and attempts have been made to describe microorganisms and metabolic activity involved in the treatment of such complex and variable by-products. However, few studies have investigated olive oil by-products in order to produce added-value ingredients and/or preservatives for food industries. This review provides an overview of the prospective of liquid olive oil by-products as a source of high nutritional value compounds to produce new functional additives or ingredients and to explore potential and future research opportunities.

Green determination of eight water-soluble B vitamins in cosmetic products by liquid chromatography with ultraviolet detection

B vitamins are a group of compounds with beneficious properties for dermatologic care, and therefore they are included in the cosmetic formulations as high added-value ingredients. In this paper, an analytical method for the simultaneous determination of eight water-soluble B vitamins in cosmetic products is reported for the first time. This method is based on liquid chromatography with ultraviolet detection (LC-UV) analysis after simple water leaching of the analytes from the cosmetic matrix. No organic solvents are required, beyond the ethanol used in the chromatographic mobile phase. The proposed method has been successfully validated showing good linearity, limits of detection in the low μg mL−1 range (from 0.14 to 0.43 μg mL−1) and good repeatability (relative standard deviation below 11 %). The accuracy of the method has been proven by the analysis of laboratory-made samples (i.e., a cream and a gel) with known concentrations of the analytes, providing low relative errors (below 12 %). Finally, the method has been successfully applied to four commercial cosmetic samples of different formulations without significant matrix effects. The results obtained and the environmentally friendly features of the method showed its usefulness for carrying out both pre- and in-market quality control of final cosmetic products.

Whey allergens: Influence of nonthermal processing treatments and their detection methods.

Whey and its components are recognized as value-added ingredients in infant formulas, beverages, sports nutritious foods, and other food products. Whey offers opportunities for the food industrial sector to develop functional foods with potential health benefits due to its unique physiological and functional attributes. Despite all the above importance, the consumption of whey protein (WP) can trigger hypersensitive reactions and is a constant threat for sensitive individuals. Although avoiding such food products is the most successful approach, there is still a chance of incorrect labeling and cross-contamination during food processing. As whey allergens in food products are cross-reactive, the phenomenon of homologous milk proteins of various species may escalate to a more serious problem. In this review, nonthermal processing technologies used to prevent and eliminate WP allergies are presented and discussed in detail. These processing technologies can either enhance or mitigate the impact of potential allergenicity. Therefore, the development of highly precise analytical technologies to detect and quantify the existence of whey allergens is of considerable importance. The present review is an attempt to cover all the updated approaches used for the detection of whey allergens in processed food products. Immunological and DNA-based assays are generally used for detecting allergenic proteins in processed food products. In addition, mass spectrometry is also employed as a preliminary technique for detection. We also highlighted the latest improvements in allergen detection toward biosensing strategies particularly immunosensors and aptasensors.

Blanching Pre-Treatment Promotes High Yields, Bioactive Compounds, Antioxidants, Enzyme Inactivation and Antibacterial Activity of 'Wonderful' Pomegranate Peel Extracts at Three Different Harvest Maturities.

‘Wonderful’ pomegranate (Punica granatum L.) peel contains a wide range of phytochemicals including vitamins, dietary fibre, phenolic compounds, and antioxidant properties. Yet, it is often used as animal feed or discarded in landfills, which is not the best eco-friendly way to utilize this phenolic-rich bioresource. Finding novel ways of utilizing pomegranate peel waste could prove a more profitable and eco-friendlier alternative that is far more beneficial to the economy. Adding a blanching pre-treatment step at optimal conditions prior to processing of pomegranate peel aids in the inactivation of quality changing enzymes such as polyphenol oxidase (PPO) and peroxidase (POD), which are accountable for the degradation reactions that cause breakdown of nutrients and phytochemicals. This study aimed to determine the effect of blanching at 80 °C for 3 min on the yield, polyphenol content, antioxidant properties, enzyme inactivation, and antibacterial activity of ‘Wonderful’ pomegranate peel ethanolic extracts from three different harvest maturities (unripe, ripe, and over ripe), including a comprehensive characterization and quantification using liquid chromatography-mass spectrometry (LC-MS). The blanched unripe peel extracts exhibited the highest total phenolic content, total tannin content, 2,2-diphenyl-1-picryl hydrazyl (DPPH) antioxidant activity, 2,2-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical scavenging activity and ferric ion reducing antioxidant power (FRAP) at 14.0 mg gallic acid equivalent (GAE)/g dry mass (DM), 1.0 mg GAE/g DM, 359.1 µmol Trolox/g DM, 912.2 µmol Trolox/g DM and 802.5 µmol Trolox/g DM, respectively. There was significant (p < 0.05) decrease in PPO and POD activity of all blanched pomegranate peel extracts. The blanched unripe peel extracts had the lowest PPO activity at 0.2 U/g fresh weight (FW), with a 70% PPO inactivation compared to ripe and over ripe harvest, whereas the highest POD inactivation was recorded at 67% in over ripe peel extracts. All blanched peel extracts, irrespective of harvest maturity, had minimum inhibitory concentration (MIC) values at 160 µg/mL against all four bacteria strains tested, which included two Gram-positive bacterial strains (Bacillus subtilis ATCC 6051 and Staphylococcus aureus ATCC 12600) and two Gram-negative bacteria (Escherichia coli 11775 and Klebsiella pneumonia ATCC 13883). A total of 25 metabolites including phenolic acids (4), organic acids (1), flavonoids (4), ellagitannins (13), and other polyphenols (3) in all three pomegranate peel samples were tentatively identified after LC-MS profiling. The blanched unripe peel extracts showed significantly higher punicalin α and β, β punicalagin, catechin, epicatechin content at 414 mg/g, and 678 mg/g, 151 mg/g, 229 mg/g, respectively, compared to peel extracts from other harvest maturities. This study provides supportive information for the commercial utilization of pomegranate fruit peel as source of value-added ingredients for the development of novel food, cosmetics, and pharmacological products.

Particulate systems from maqui (Aristotelia chilensis) wastes to be used as nutraceutics or high value-added ingredients

Powdered ingredients from maqui wastes were produced and the effect of drying method (air- and freeze-drying) and particle size on physicochemical and bioactive properties was investigated. Among the particulate systems of smaller particle size that showed the most balanced insoluble to soluble fiber ratio and the best hydration and oil absorption properties, the freeze-dried ones presented the best retention of polyphenols, anthocyanins, and antioxidant capacity. These powders could be used as ingredients in premixes for the development of foods for diabetes or gluten-free diets. The powders of higher granulometry presented excellent flowability and more dispersed particle size distribution, being more adequate for the development of composite foods or nutraceutics.

Helichrysum italicum (Roth) G. Don Essential Oil from Serbia: Chemical Composition, Classification and Biological Activity—May It Be a Suitable New Crop for Serbia?

H. italicum essential oil (EO) is one of the most popular ingredients utilized by the cosmetic industry, and it is also used as natural antioxidant and as a value-added ingredient in food products. The chemical composition of the EO H. italicum cultivated in Serbia was analyzed by gas chromatography–mass spectrometry. The quantitative structure–retention relationship was used to predict the retention indices of the EO constituents acquired by GC-MS data, applying five molecular descriptors selected by factor analysis and a genetic algorithm. Also, antimicrobial activity, and biological activity by four common antioxidant tests (DPPH and ABTS assays, reducing power, and β-carotene bleaching test), and in vitro antihyperglycemic and anti-inflammatory capacities were evaluated. A total of 70 EO constituents were detected, of which 17 (8.5%) could not be identified. The H. italicum EO in this study belonged to γ-curcumene chemotype. The coefficients of determination reached the value of 0.964, demonstrating that this model could be used for prediction purposes. All applied tests showed that H. italicum EO possesses good biological activity and an interesting chemical composition. Therefore, the EO of H. italicum grown in Serbia has a potential to be used in food, cosmetic, and pharmaceutical products.

Interactions between Blackcurrant Polyphenols and Food Macronutrients in Model Systems: In Vitro Digestion Studies.

Blackcurrant pomace, rich in fiber and polyphenols, can be used as added-value ingredient for food formulation. However, the bounding of polyphenols to pomace and the interactions that take place with food nutrients modify polyphenol bioaccessibility. This work studied the interactions between polyphenols and the main macronutrients in foods, and the changes that occurred during in vitro digestion, using model systems. Model systems were formulated with (i) water, (ii) wheat starch, (iii) olive oil, (iv) whey protein, and (v) a model combining all the ingredients. Polyphenols were added from two sources: as pomace and as a polyphenolic pomace extract. Interactions between polyphenols and macronutrients were studied using light microscopy; total phenolic content (TPC) and antioxidant capacity (AC) were determined before and after the in vitro digestion process. Lastly, the bioaccessibility of the samples was calculated. Polyphenols incorporated into the model systems as pomace increased their bioaccessibility if compared to polyphenols added as extract. For single-nutrient model systems formulated with pomace, the bioaccessibility was higher than when the system contained all the nutrients. Of all the components studied, the greatest effect on bioaccessibility was observed for proteins.

The next-generation biomass for biorefining

Biorefining, which uses biomass as feedstock and converts it into valuable products, is a core technology for the sustainable green industry and has high potential as an alternative to the current petrochemical-based industry. This article covers the requirements for feedstock that should be met for the economic feasibility of a biorefinery. In particular, organic waste that meets several requirements as the next-generation biomass has high potential. However, the complex and significant differences in composition depending on the origin make it difficult to follow the previous system of classification such as cellulose, hemicellulose, and lignin. In particular, several organic wastes contain high value-added bioactive components. Therefore, a strategy for the effective use of high value-added ingredients contained in trace amounts is required, which is briefly introduced in the third section of this article.

A review study on whey protein &amp; its health benefits

Whey, a component of milk, is co-product of cheese-making and casein production in the dairy industry. Nowadays, whey is regarded as a value-added component in many food items. Whey and whey components are regarded as value-added ingredients in baby formulae, sports nutrition meals and drinks, and other food items. Recognition of whey as a source of different biologically active chemicals with distinct physiological and functional characteristics offers possibilities for the food industry to create functional meals or foods that have potential health advantages. Whey-derived bioactive components have antimicrobial and antiviral properties, and enhance immune defense and bone health, and improve ant oxidative activity, and help protect against cancer and cardiovascular disease, and enhance the performance of physically active individuals, among other benefits. The current review is an effort to address scientific elements of whey proteins’ health advantages and criticize some of the major research results connected with them to date.

Potential development of non-synthetic food additives from orange processing by-products—a review.

Abstract Citrus is the largest fruit crop worldwide. Meanwhile, oranges account for 60 per cent of the total, with their main application in juice production. During orange juice production, only about 50 per cent of the fresh orange weight is transformed into juice, with the remaining 50 per cent comprised of residue (peel, pulp, seeds, orange leaves and whole orange fruits that do not reach the quality requirements). With the resulting tons of orange by-products, there has been an initiative to research possible ways to reutilize and revalorize citrus waste. Orange pomace, the by-product from juicing process, is currently used to extract the essential oils for fragrance and flavor, and a majority of the waste is used as cattle feed; however, these applications do not account for all of the waste or capture all of its potential value. Meanwhile, these by-products are put into landfills at the owner’s expense, and contribute to global warming through carbon emissions. On the other hand, orange by-products still contain many useful nutraceutical components, such as dietary fiber and phytochemicals, which could be utilized for value-added ingredients and new product development. Some research approaches in this area include the production of organic fertilizers and biofuels, or the extraction of essential oils, pectins, and antioxidant compounds. There is little information in the literature and in the food industry in terms of utilizing the orange pomace directly or with some simple treatments. Orange pomace may be used for food product development as a ‘clean-label’, non-synthetic preservative, which rationalizes this review.

Physical, chemical, and technofunctional properties of okara modified by a carbohydrase mixture

A carbohydrase mixture (cellulase, hemicellulase, arabanase, β-glucanase, and xylanase) was used to hydrolyze cell wall polysaccharides present in okara to increase soluble fiber and improve hydration properties. Hydrolysis was carried out at different enzyme concentrations (0.1–1.0%) and reaction temperatures (20–55 °C) using a central composite rotatable design. Temperature range was selected on the basis of enzyme manufacturer's recommendations. Optimal hydrolysis conditions for simultaneous maximization of soluble fiber, water absorption and holding capacity, and swelling capacity were determined, and the physical, chemical, and technofunctional characteristics of modified okara were analyzed. Hydrolysis under optimal conditions (0.8% enzyme, 46 °C, 3 h) increased soluble fiber content by 105%, water absorption and holding capacity by 34%, and swelling capacity by 13%. Modified okara particles were found to be more porous and fragmented than control. Treatment also altered color and chemical composition, leading to a decrease in insoluble fibers combined with an increase in soluble fibers and sugars. Oil absorption and holding capacity was enhanced by 73%, but solids stability in water and protein solubility in water were not affected. Hydrolysis proved to be an effective method for improving okara physicochemical properties for future applications, converting this residue into a potentially value-added ingredient.

Strategic considerations for establishing a large-scale seaweed industry based on fish feed application: a Norwegian case study

Soy protein concentrate (SPC) is a key ingredient in fish feed and most of it originates from Brazil. However, the Brazilian soy industry has reportedly resulted in significant environmental problems including deforestation. Consequently, new sources for protein are investigated and protein extracted from farmed seaweed is considered an alternative. Therefore, we investigate how seaweed protein product (SPP) can compete against SPC as a protein ingredient for fish feed. The study uses the positioning matrix, cost analyses involving the power law, and uncertainty analysis using Monte Carlo simulations, and key research challenges are identified. The initial finding is that, with the emerging seaweed industry, the cost of producing SPP is too high to be competitive for fish feed applications. To overcome this challenge, two solutions are investigated. First, substantial investments in cultivation and processing infrastructure are needed to accomplish scale, and a break-even scale of 65,000 tonnes is suggested. The second but more promising avenue, preferably in combination with the former, is the extraction of seaweed protein and high-value seaweed components. With mannitol and laminaran as co-products to the SPP, there is a 25–30% probability of a positive bottom line. Researches on extraction processes are therefore a necessity to maximize the extraction of value-added ingredients. Over time, it is expected that the competitive position of SPP will improve due to the upscaling of the volume of production as well as better biorefinery processes.

Predictive Consumer Acceptance Models and Quality Attributes for Cookies Enriched with Potato Protein Isolate and Concentrate

Potato protein isolate and concentrate, recovered from a waste stream from the starch industry, potato fruit juice, were assessed as added-value ingredients for the enrichment of composite flours composed of wheat and rice flours with varying ratios to improve the quality attributes of reduced-gluten cookies. Bridging the analytical textural properties to the sensory results of a semi-trained panel contributed to the understanding of the quality attributes (textural, color, and sensory) that drive the overall acceptance. Potato protein isolate resulted in cookies, which bent more on first bite and were more texturally desired by a semi-trained panel compared with cookies prepared with potato protein concentrate. The effects of rice flour proportion (14.6–85.4%) and potato protein isolate enrichment (1.9–23.1%) were investigated using a central composite rotatable design. Logistic regression analysis of the sensory results (70 consumers) revealed that liking scores of overall liking, aftertaste, and crispness were the most determinants for the overall acceptance of reduced-gluten cookies enriched with potato protein isolate. Predictive mathematical models of the liking scores of these critical sensory attributes were developed. Based on the models, the level of potato protein isolate enrichment up to 7.2% produced acceptable reduced-gluten cookies, while improving the textural and sensorial characteristics when compared with rice flour alone.

Winemaking Byproducts as Source of Antioxidant Components: Consumers' Acceptance and Expectations of Phenol-Enriched Plant-Based Food.

One of the food industry’s priorities is to recover byproducts and move towards more sustainable systems. Among wine-chain byproducts, unripe grapes represent a promising source of antioxidants. However, the development of new foods enriched using phenol-rich ingredients is challenging due to their sensory attributes. The aims of the present study were to (1) use phenol-rich extract from unripe grapes to enrich a model plant-based food (beetroot puree—BP); (2) evaluate consumers’ acceptance and expectations for the beetroot purée samples. The effect of information about the sustainability and pro-health activity of value-added ingredients on consumers’ responses was also investigated. Four beetroot purees with increasing concentrations of phenol extract (0–1.93 g/kg) added were evaluated by 101 participants in three tasting conditions (blind: only samples; expected: only information without tasting; real: both samples and information).Liking slightly decreased with increasing concentrations of phenol extract, even if all the samples were considered acceptable. The health and sustainability information increased the hedonic expectations, although it was not assimilated by all consumers involved. The development of new phenol-enriched foods using functional ingredients from unripe grapes is challenging. However, it is also promising, since all the samples were generally accepted by the consumers and they presented phenol levels that were stable over time and that could have positive health effects when consumed.