Changes of Anthocyanins, Anthocyanidins, and Antioxidant Activity in Bilberry Extract during Dry Heating

Polyphenols and Maillard Reaction Products in Dried Prunus spinosa Fruits: Quality Aspects and Contribution to Anti-Inflammatory and Antioxidant Activity in Human Immune Cells Ex Vivo

Dried Prunus spinosa fruits (sloes) are folk phytotherapeutics applied to treat chronic inflammatory disorders. However, their pharmacological potential, activity vectors, and drying-related changes in bioactive components remain unexplored. Therefore, the present research aimed to evaluate the anti-inflammatory and antioxidant effects of dried sloes in ex vivo models of human neutrophils and peripheral blood mononuclear cells (PMBCs) and establish their main active components. It was revealed that the fruit extracts significantly and dose-dependently inhibited the respiratory burst, downregulated the production of elastase (ELA-2) and TNF-α, and upregulated the IL-10 secretion by immune cells under pro-inflammatory and pro-oxidant stimulation. The slightly reduced IL-6 and IL-8 secretion was also observed. The structural identification of active compounds, including 45 phenolics and three Maillard reaction products (MRPs) which were formed during drying, was performed by an integrated approach combining LC-MS/MS, preparative HPLC isolation, and NMR studies. The cellular tests of four isolated model compounds (chlorogenic acid, quercetin, procyanidin B2, and 5-hydroxymethylfurfural), supported by statistical correlation studies, revealed a significant polyphenolic contribution and a slight impact of MRPs on the extracts’ effects. Moreover, a substantial synergy was observed for phenolic acids, flavonoids, condensed proanthocyanidins, and MPRs. These results might support the phytotherapeutic use of dried P. spinosa fruits to relieve inflammation and establish the quality control procedure for the extracts prepared thereof.

Investigation of Chemical Compositions and Biological Activities of Mentha suaveolens L. from Saudi Arabia

Mentha is an aromatic plant used since antiquity for its pharmaceutical virtues. The climate of Saudi Arabia favors the growth of aromatic plants including Mentha suaveolens L. The aim of this study is to analyze the volatile oils of different parts of fresh and dried Mentha suaveolens L. grown in Saudi Arabia (Aljouf area) using Gas Chromatography/Mass Spectrometry (GC/MS) and Gas Chromatography Flame Ionization Detector (GC/FID) techniques, to recognize the effect of drying on chemical composition, then to evaluate the antioxidant and antifungal activities of different extracts. In total, 118 compounds were identified via GC/MS and GC/FID, in which carvone is the main volatile constituent (stems, leaves, whole plant 45–64%). This investigation deduces that Mentha belonged to the carvone chemotype. Then, the analysis of non-volatile constituents of fresh and dried Mentha was performed by HPLC. The main phenolic compound of fresh and dried Mentha for different parts was rosmarinic acid (ranging from 28,002.5 to 6558 µg/g). The ethanolic extract of fresh stem showed the highest antifungal activity (53% inhibition) compared with miconazole (60% inhibition) but the ethanoic extract of dry stem showed no activity. Additionally, all ethanolic extracts, whether for fresh or dry Mentha, have antioxidant activity more than 90% while the antioxidant activity of whole plant volatile oil is equal to 53.33%. This research shows that M. suaveolens L. could be applied to manufacture natural antioxidants, antifungal, and flavoring agents.

Mortiño (Vaccinium floribundum Kunth): An Underutilized Superplant from the Andes

Mortiño is a member of the Ericaceae family native to the Andes that has been used by local communities for centuries. This species has shown potential in the areas of medicine, agronomy, and green technology. We used a multidisciplinary approach to review aspects related to the ecology, horticulture, composition and potential biotechnological applications of mortiño. As interest in this species grows, care must be taken to identify opportunities that justify its sustainable use while emphasizing the development of local communities. Mapping the wide variety of potential uses and the current state of conservation and utilization of this berry will help researchers to better target mortiño’s potential.

Experimental and theoretical research on the effect of coupling heat and pH on the structure and antioxidant activity of cyanidin-3-O-glucoside from black soybean coat

BACKGROUND

Since anthocyanin has good coloration and antioxidant properties, many studies have focused on exploring the stability and antioxidant activity of anthocyanin. The objective of this work was to study effects of pH and temperature on the bioactivity of cyanidin-3-O-glucoside (C3G) and ultra-performance liquid chromatography-photodiode array-electrospray ionization-quadrupole-time-of-flight mass spectrometry (UPLC-PDA-ESI-Q-TOF-MS) and density functional theory (DFT) were used to explain the mechanism of structural transformation of C3G affecting their bioactivity at the molecular level.

RESULTS

During the heating process at pH 2.2 to 7.0，the flavylium cation content of C3G decreased from 92.71% to 51.64% and the chalcone content increased from 7.29% to 30.61%. The quinoidal base and first discovery of the degradation product of the C3G, 1-(3,4-dihydroxy-phenyl)-2-(3, 4,5-trihydroxy-6-hydroxymethyl-tetrahydro-pyran-2-yloxy)-ethanone, were only detected in heated samples at pH 7.0. DFT revealed the antioxidant mechanism was mediated by sequential proton loss electron transfer and the antioxidant activity of C3G in pH 5.0 and 7.0 environments was higher than that in the pH 2.2 environment.

CONCLUSIONS

The results revealed the thermal degradation products of C3G included catechin, 3,4-dihydroxybenzoic acid, 2,4,6-trihydroxy-benzaldehyde and 1-(3,4-Dihydroxy-phenyl)-2-(3,4,5-trihydroxy-6-hydroxymethyl-tetrahydro-pyran-2-yloxy)-ethanone. C3G had higher antioxidant activity in weakly acidic to near-neutral environments and the reactive sites were most likely at the 4'-OH and 5-OH sites. © 2021 Society of Chemical Industry.

Anticancer and Cytotoxicity Activity of Native and Modified Black Rice Flour on Colon Cancer Cell Lines

This study is intended to evaluate the cytotoxicity of native and dual-modified black rice flour against the colon cancer cell line (HCT116) and mouse embryo cell line (3T3-L1) by using the MTT assay. The modification techniques applied to prepare rice flour samples were enzymatic modification and heat moisture treatment. In this study, the IC50 of native black rice flour and modified black rice flour was 255.78 µg/mL and 340.85 µg/mL, respectively. The result confirms that the native black rice flour has significant cytotoxic and anticancer potential against human colon cancer cells. In addition, the IC50 of native black rice flour and modified black rice flour on the 3T3-L1 cell line was found to be 345.96 µg/mL and 1106.94 µg/mL, respectively. The results showed that the native black rice flour had weak cytotoxicity, and modified black rice flour was nontoxic in both the cell lines. The active component of phytochemicals present in black rice flour has a potential role in preventing colon cancer.

Anthocyanins and Functional Compounds Change in a Third-Generation Snacks Prepared Using Extruded Blue Maize, Black Bean, and Chard: An Optimization

The effect of extrusion cooking on bioactive compounds in third-generation snacks (TGSE) and microwave-expanded snacks (MWSE) prepared using black bean, blue maize, and chard (FBCS) was evaluated. FBCS was extruded at different moisture contents (MC; 22.2–35.7%), extrusion temperatures (ET; 102–142 °C), and screw speeds (SP; 96–171 rpm). Total anthocyanin content (TAC), contents of individual anthocyanins, viz., cyanidin-3-glucoside, malvidin-3-glucoside, pelargonidin-3-glucoside, pelargonidin-3-5-diglucoside, and delphinidin-3-glucoside chloride, total phenolic content (TPC), antioxidant activity (AA), and color parameters were determined. TAC and individual anthocyanin levels increased with the reduction in ET. ET and MC affected the chemical and color properties; increase in ET caused a significant reduction in TPC and AA. Microwave expansion reduced anthocyanin content and AA, and increased TPC. Extrusion under optimal conditions (29% MC, 111 rpm, and 120 °C) generated products with a high retention of functional compounds, with high TAC (41.81%) and TPC (28.23%). Experimental validation of optimized process parameters yielded an average error of 13.73% from the predicted contents of individual anthocyanins. Results suggest that the TGSE of FBCS obtained by combining extrusion and microwave expansion achieved significant retention of bioactive compounds having potential physiological benefits for humans.

A Review of the Current Knowledge of Thermal Stability of Anthocyanins and Approaches to Their Stabilization to Heat

Anthocyanins are colored valuable biocompounds, of which extraction increases globally, although functional applications are restrained by their limited environmental stability. Temperature is a critical parameter of food industrial processing that impacts on the food matrix, particularly affecting heat-sensitive compounds such as anthocyanins. Due to the notable scientific progress in the field of thermal stability of anthocyanins, an analytical and synthetic integration of published data is required. This review focuses on the molecular mechanisms and the kinetic parameters of anthocyanin degradation during heating, both in extracts and real food matrices. Several kinetic models (Arrhenius, Eyring, Ball) of anthocyanin degradation were studied. Crude extracts deliver more thermally stable anthocyanins than purified ones. A different anthocyanin behavior pattern within real food products subjected to thermal processing has been observed due to interactions with some nutrients (proteins, polysaccharides). The most recent studies on the stabilization of anthocyanins by linkages to other molecules using classical and innovative methods are summarized. Ensuring appropriate thermal conditions for processing anthocyanin-rich food will allow a rational design for the future development of stable functional products, which retain these bioactive molecules and their functionalities to a great extent.

Effect of Heat Treatment and Light Exposure on the Antioxidant Activity of Flavonoids

The application of food processes can lead to a modification of both the structure and the activities of flavonoids. In this article, the effect of heat treatment and exposure to light on the antioxidant activity of 6 model flavonoid solutions (rutin, naringin, eriodictyol, mesquitol, luteolin, and luteolin 7-O-glucoside) was studied. The evolution of the antioxidant activity measured after heat treatment of 130 °C at 2 h and an exposure to visible light for 2 weeks is measured by the ABTS (2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) method and represented by a new parameter called ΔTEAC. The model solution of Mesquitol showed the highest increase in ΔTEAC after a heat treatment, a value of 200 mM was obtained. The increase in ΔTEAC is always greater with thermal treatment than with light exposure. Thus, temperature and light lead to different degradation pathways of the flavonoid. In vivo measurements were carried out with solutions of naringin, erodictyol, and luteolin 7-O-glucoside. Heated solutions of flavonoids do not exhibit toxicity on cells. The specific activities of superoxide dismutase and glutathione peroxide have been determined and have shown an increased impact on the potential anti-cancer of these solutions by enhancing their cellular antioxidant activity, as well as modulation of the oxidative stress.

Orally administered pressure-blanched white saffron (Curcuma mangga Val.) improves antioxidative properties and lipid profiles in vivo

This research focused on studying the effects of orally administered pressure-blanched white saffron on the antioxidative properties and lipid profiles of wistar rats. White saffron was blanched in autoclave for 2.5, 5, 7.5, and 10 min at 100, 105, 110, 115, and 120 °C, which are equivalent to 14.71, 17.53, 20.79, 24.54, and 28.81 psia, respectively. A total of 30 male wistar rats aged four weeks were fed with a standard diet (N), oxidized peanut oil diet + unblanched white saffron (A), oxidized peanut oil diet + blanched white saffron (B), oxidized peanut oil diet + pressure-blanched white saffron (C), and oxidized peanut oil diet + aquadest (NC), for two weeks after pre-treatment with the standard diet for a week. Invivo study showed treatment with pressure-blanched white saffron could significantly improve SOD, Vitamin E, and HDL levels compared to the negative control (NC); 686.44 U/g Hb, 10.87 μg/mL, and 94.17 mg/dL versus 405.37 U/g Hb, 7.44 μg/mL, and 43.47 mg/dL, respectively. Meanwhile, treatment with pressure-blanched white saffron could significantly reduce MDA, total cholesterol, LDL, and triglyceride levels in the blood compared to the negative control (NC); 1.98 mmol/L, 108.74 mg/dL, 40.99 mg/dL, and 78.06 mg/dL versus 8.54 mmol/L, 232.46 mg/dL, 149.17 mg/dL, and 172.61 mg/dL, respectively. The results showed that pressurized blanching could significantly increase antioxidant levels of white saffron, and its dried form could improve antioxidative properties and lipid profiles in vivo.

Sonodegradation of cyanidin-3-glucosylrutinoside: degradation kinetic analysis and its impact on antioxidant capacity in vitro

BACKGROUND

As an alternative preservation method for thermal treatment, ultrasound comprises a novel non-thermal processing technology that can significantly avoid undesirable nutritional changes. However, the recent literature indicates that anthocyanin degradation occurs when ultrasound is applied in juice at high amplitude parameters. Such work has mainly focussed on the effect of ultrasound on stability, the antioxidant capacity of cyanidin-3-glucosylrutinoside (Cy-3-glc-rut) and the correlation between anthocyanin degradation and ·OH generation in a simulated system.

RESULTS

The spectral intensities of Cy-3-glc-rut at 518 and 282 nm decreased with increasing ultrasound power and treatment time. The degradation of Cy-3-glc-rut was consistent with first-order reaction kinetics (r²  > 0.9000) and there was a good linear correlation between anthocyanin degradation and hydroxyl radical formation induced by ultrasound (r²  = 0.9258). Moreover, a decrease in the antioxidant activity of Cy-3-glc-rut after ultrasound evaluated by the 1,1-diphenyl-2-picrylhydrazyl and ferric reducing antioxidant power methods was observed.

CONCLUSION

Overall, the results of the present study show that ultrasound will accelerate the degradation of Cy-3-glc-rut with the growth of power over time. © 2016 Society of Chemical Industry.

Stability, Antioxidant Capacity and Degradation Kinetics of Pelargonidin-3-glucoside Exposed to Ultrasound Power at Low Temperature

As an alternative preservation method to thermal treatment, ultrasound is a novel non-thermal processing technology that can significantly avoid undesirable nutritional changes. However, recently literature indicated that anthocyanin degradation occurred when high amplitude ultrasound was applied to juice. This work mainly studied the effect of ultrasound on the stability and antioxidant capacity of pelargonidin-3-glucoside (Pg-3-glu) and the correlation between anthocyanin degradation and •OH generation in a simulated system. Results indicated that the spectral intensities of Pg-3-glu decreased with increasing ultrasound power (200–500 W) and treatment time (0–60 min). The degradation trend was consistent with first-order reaction kinetics (R² > 0.9100). Further study showed that there was a good linear correlation between Pg-3-glu degradation and •OH production (R² = 0.8790), which indicated the important role of •OH in the degradation of anthocyanin during ultrasound exposure. Moreover, a decrease in the antioxidant activity of solution(s) containing Pg-3-glu as evaluated by the DPPH and FRAP methods was observed after ultrasound treatment.

Effect of processing on phenolic antioxidants of fruits, vegetables, and grains--a review

Understanding the influence of processing operations such as drying/dehydration, canning, extrusion, high hydrostatic pressure, pulsed electric field, and ohmic heating on the phytochemicals of fruits, vegetables, and grains is important in retaining the health benefiting properties of these antioxidative compounds in processed food products. Most of the previous investigations in the literature on the antioxidants of fruits, vegetables, and grains have shown that food-processing operations reduced the antioxidants of the processed foods, which is also the usual consumer perception. However, in the last decade some articles in the literature reported that the evaluation of nutritional quality of processed fruits and vegetables not only depend on the quantity of vitamin C but should include analyses of other antioxidant phytochemicals and antioxidant activity. Thermal processing increased the total antioxidant activity of tomato and sweet corn. Most importantly, analysis also depends on the condition, type, and mechanism of antioxidant assays used. This review aims to provide concise information on the influence of various thermal and nonthermal food-processing operations on the stability and kinetics of health beneficial phenolic antioxidants of fruits, vegetables, and grains.

Specific Anthocyanin Contents of Whole Blue Maize Second-Generation Snacks: An Evaluation Using Response Surface Methodology and Lime Cooking Extrusion

Lime cooking extrusion (LCE) is a widely applied technology for producing second-generation snacks, as an alternative to traditional nixtamalization (TN). Pigmented maize has been used to produce snacks with similar organoleptic characteristics to TN products and to obtain a product with additional functional benefits due to the anthocyanic compounds contained in those grains. However, during the process, anthocyanins are degraded, and several chemical modifications occur. Response surface methodology is applied to evaluate extrusion factors and their effects on the response variables of extrudates. The aim of this study was to evaluate the changes in specific anthocyanins after extrusion in second-generation blue maize snacks. Three anthocyanins were identified and quantified by HPLC-UV-DAD: cyanidin 3-glucoside and pelargonidin 3-glucoside, which have been previously reported in blue maize and its products, and cyanidin 3,5-diglucoside. Higher retention values were found in the extrudates making LCE a viable option for producing second-generation blue maize snacks.

Degradation of (-)-epicatechin and procyanidin B2 in aqueous and lipidic model systems. first evidence of "chemical" flavan-3-ol oligomers in processed cocoa

Despite the key role of flavan-3-ols in many foods, very little is yet known concerning the modification of their chemical structures through food processes. Degradation of model media containing (-)-epicatechin and procyanidin B2, either separately or together, was monitored by RP-HPLC-DAD-ESI(-)-MS/MS. Medium composition (aqueous or lipidic) and temperature (60 and 90 °C) were studied. In aqueous medium at 60 °C, (-)-epicatechin was mainly epimerized to (-)-catechin, but it was also oxidized to "chemical" dimers, a "chemical" trimer, and dehydrodi(epi)catechin A. Unlike oxidation, epimerization was enhanced at 90 °C. In lipidic medium, epimerization proved slow but degradation was faster. Procyanidin B2 likewise proved able to epimerize, especially at 90 °C and in aqueous medium. At high temperature only, the interflavan linkage was cleaved, yielding the same compounds as those found in the monomer-containing model medium. Oxidation to procyanidin A2 was also evidenced. With little epimerization and slow oxidation even at 90 °C, procyanidin B2 proved more stable in lipidic medium. Synergy was also observed: in the presence of the monomer, the dimer degradation rate increased 2-fold at 60 °C. This work states for the first time the presence of newly formed flavan-3-ol oligomers in processed cocoa.

Effects of short-term heating on total polyphenols, anthocyanins, antioxidant activity and lectins of different parts of dwarf elder (Sambucus ebulus L.)

Dwarf elder (Sambucus ebulus L.) berries are rich in health-promoting phytochemicals such as polyphenols and anthocyanins, and display a significant antioxidant activity. They are also rich in two lectins (ebulin f and SELfd) that share amino acid sequence homology with the elderberry allergen Sam n1 present in Sambucus nigra pollen and fruits. Ebulin f displays toxicity by oral ingestion. This study was aimed at eliminating the toxicity of these lectins whilst having little or no effect on the antioxidant properties of dwarf elder berries. We thus investigated the potential effects of incubation in a boiling water bath of extracts from several parts of the plant on total polyphenol content, antioxidant activity, total anthocyanins, cyanidin-3-glycoside content, and the sensitivity of purified dwarf elder fruit lectins to a simulated gastric fluid. The study shows that five minutes of said heat treatment fully sensitized both lectins to pepsin digestion, whilst minimally reducing phenol and antioxidant as well as free radical scavenging activities to below 13%. It proved possible to eliminate the potential risks derived from the presence of lectins in dwarf elder juices without any significant reduction in the content of the antioxidant compounds. Dwarf elder berries may thus be a valuable nutritional source.

Thermal degradation of grape marc polyphenols

Bioactive compounds of wine making by-products are of interest in food, cosmetics and pharmaceutical industries. Extraction of antioxidants under mild conditions is time-consuming, giving ground to the development of intensification processes where the operation at high temperature may deteriorate extract quality. This study examined thermal degradation of grape marc and its filtered extract (80, 100 and 150°C). The decrease in anthocyanin content was modelled under non-isothermal conditions by first order kinetics, using the Arrhenius equation. Simulated degradation under isothermal heating showed that the grape marc is more sensitive by one order of magnitude to heat than the filtered extract. This tendency was also confirmed by analyses of the total phenolic content and antioxidant activity. It is suggested that an optimal combination of temperature, treatment time and also raw material environment could be found in process intensification.

Phytochemicals in sweet sorghum ( Dura ) and their antioxidant capabilities against lipid oxidation

Hydrophilic (HPE) and lipophilic (LPE) extracts were obtained from the Louisiana sweet sorghum millets. Nine major hydrophilic phytochemicals were quantified at levels of 8.9 μg/g for cinnamic acid to 1570.0 μg/g for apigeninidin. Lipophilic phytochemicals (α- and γ-tocopherol, lutein, and β-carotene) were quantified at levels of 7.7, 145.7, 4.8, and 18.8 μg/g, respectively. The total phenolic contents of HPE and LPE were 768.9 and 97.6 μg of catechin equivalent/g, respectively, while DPPH activities were 6.5 and 0.8 μmol of Trolox equivalent/g for HPE and LPE, respectively. In an emulsion model, HPE exhibited higher capability of inhibiting cholesterol oxidation and stabilizing linoleic acid than LPE. Inhibition rates of cholesterol oxidation for HPE and LPE at 40 μg/mL were 92.2% and 65.4%, respectively. Retention rates of linoleic acid were 70.4% for HPE and 33.6% for LPE at a given concentration. Thus, HPE of sweet sorghum millet has potential in functional food applications.

Antioxidant-rich phytochemicals in miracle berry (Synsepalum dulcificum) and antioxidant activity of its extracts

Miracle berry is known for its unique characteristic of modifying sour flavours to sweet. Twelve phenolics were identified and quantified in the miracle berry flesh at a level from 0.3 for kaempferol to 17.8 mg/100g FW for epicatechin. Lutein and α-tocopherol were also quantified at a level of 0.4 and 5.8 mg/100g FW, respectively. The TP and TF contents were 1448.3 GA and 9.9 QR mg Equiv/100g FW for the flesh, respectively, compared with 306.7 GA and 3.8 mg QR mg Equiv/100g FW of the seeds. The free radical scavenging and reducing percentage of the flesh extract was 96.3% and 32.5% in DPPH and ABTS assays, respectively. Additionally, the flesh extract had a high FRAP of 22.9 mmol/100g. It significantly inhibited the oxidation of PUFA in fish oil as well. Thus, miracle berry could also serve as an antioxidant-rich fruit to provide health promoting function.

Effect of green tea extract microencapsulation on hypertriglyceridemia and cardiovascular tissues in high fructose-fed rats

The application of polyphenols has attracted great interest in the field of functional foods and nutraceuticals due to their potential health benefits in humans. However, the effectiveness of polyphenols depends on their bioactivity and bioavailability. In the present study, the bioactive component from green tea extract (GTE) was administrated orally (50 mg/kg body weight/day) as free or in a microencapsulated form with maltodextrin in rats fed a high fructose diet. High fructose diet induced features of metabolic syndrome including hypertriglyceridemia, hyperuricemia, increased serum total cholesterol, and retroperitoneal obesity. In addition, myocardial fibrosis was increased. In rats receiving high fructose diet, the lowering of blood triglycerides, total cholesterol, non esterified fatty acid (NEFA) and uric acid, as well as the reduction in final body weight and retroperitoneal fat weight associated with the administration of GTE, led to a reversal of the features of metabolic syndrome (P < 0.05). In particular, the administration of microencapsulated GTE decreased myocardial fibrosis and increased liver catalase activity consistent with a further alleviation of serum NEFA, and hyperuricemia compared to administration of GTE. Taken together, our results suggest that microencapsulation of the bioactive components of GTE might have a protective effect on cardiovasucular system by attenuating the adverse features of myocardial fibrosis, decreasing uric acid levels and increasing hepatic catalase activity effectively by protecting their bioactivities.

Release and degradation of anthocyanins and phenolics from blueberry pomace during thermal acid hydrolysis and dry heating

In this study, blueberry pomace was soaked in pH 1, 4, or 7 solution for 10 min followed by boiling hydrolysis. Nine anthocyanins and 11 other phenolic compounds were released after acid hydrolysis. The highest anthocyanin release (4.70 mg/g) was achieved by boiling at pH 1 for 15 min followed by 3.94 mg/g at pH 4 and 3.46 mg/g at pH 7. Phenolics were released more quickly than anthocyanins during boiling. The change of antioxidant activity of the pomace during boiling was correlated with the total phenolic content but not anthocyanin content. The degradation rate of anthocyanins during boiling eventually surpassed the release rate from the pomace. Protocatechuic acid and catechin continuously increased during heating. Dry heat resulted in continuous degradation of anthocyanins and other phenolics in the pomace. The reduction in antioxidant activity of the pomace during dry heating was correlated with both the phenolic and anthocyanin contents.

Quality factors, antioxidant activity, and sensory properties of jet-tube dried rabbiteye blueberries

BACKGROUND

Rabbiteye blueberries are an excellent source of nutrients and phytochemicals. They are often dried, which can degrade health-promoting compounds. Means of shortening exposure to high-temperature drying air are desirable. Five cultivars of rabbiteye blueberries ('Premier', 'Tifblue', 'Brightwell', 'Alapaha', and 'Powderblue') were dried in a jet-tube fluidized bed air dryer with varying pretreatments including mechanical abrasion and osmotic dehydration.

RESULTS

Drying time ranged from 66 to 95 min at 107 °C, achieving a final water activity of 0.347-0.605. Prior osmotic dehydration significantly reduced the drying time. Vacuum osmotic dehydration for 70 min achieved similar moisture contents to soaking blueberries for 24 h. Jet-tube dried blueberries exhibited greater color saturation than commercially available blueberries. While drying reduced the total monomeric anthocyanin (TMA) content, this occurred to a lesser extent than by other processing methods. The total phenolics content (TPC) and antioxidant capacity (H-ORACFL values) increased after drying. 'Premier' was the most preferred vacuum-infused dried blueberry, with a water activity (aw) of 0.53 and 157 g H2O kg(-1). 'Tifblue' was most preferred amongst the overnight-infused and also unsweetened dried blueberries.

CONCLUSION

Jet-tube drying can substantially reduce drying times while yielding blueberries with good color, sensory properties, TMA, TPC, and H-ORACFL values. Furthermore, some cultivars produce better-quality dried blueberries than others.

Comparison of the activities of hydrophilic anthocyanins and lipophilic tocols in black rice bran against lipid oxidation

The antioxidant capabilities of anthocyanin and tocol extracts from black rice bran were evaluated using an emulsion system containing either cholesterol (1.0mg/ml) or fish oil (10mg/ml). The cholesterol oxidation product, 7-ketocholesterol, increased to 180.1 μg/ml in the control emulsion after 168 h of oxidation, while it was only 15.4 and 39.0 μg/ml in the emulsions containing 1 μg/ml of the anthocyanin and tocol extracts, respectively; but below 1.2 μg/ml in the emulsion having 5 μg/ml of anthocyanins or tocols. In the fish oil emulsion, over 80% of C20:5 and C22:6 were oxidised after a 48 h incubation at 37°C, while they were retained above 38% and 65% in the emulsions containing 10 μg/ml of anthocyanins and tocols, respectively, and above 85% in the emulsion containing 20 μg/ml of anthocyanins or tocols. Compared with the tocols extract, the capability of the anthocyanin extract was relatively greater in stabilising cholesterol but lower in inhibiting fatty acids oxidation.

Isolation of bilberry anthocyanidin 3-glycosides bearing ortho-dihydroxyl groups on the B ring by forming an aluminum complex and their antioxidant activity

Bilberry anthocyanin bearing an ortho-dihydroxyl group on the B ring was selectively isolated by complex formation with flavocommelin and aluminum ions (Al(3+)). The interaction between the anthocyanins, flavocommelin, and Al(3+) might have happened in a manner similar to rigid supramolecules, such as commelinin, protocyanin, and other complex pigments. Complex blue pigment (CP, 8.85 ± 0.26 mg) with Al(3+) was formed from 18.6 mg (15 μmol) of bilberry pigment, 18.2 mg (30 μmol, 2.0 equiv) of flavocommelin, and 0.03 mL of 0.5 M aluminum chloride aqueous solution (15 μmol, 1.0 equiv), yielding 36.5 ± 0.7% recovery of anthocyanins in the complex after precipitation by ethanol. Consequently, anthocyanins bearing ortho-dihydroxyl groups on the B rings (delphinidin 3-glycosides, cyanidin 3-glycosides, and petunidin 3-glycosides) predominating (98.0 ± 0.2%) in the complex were selectively isolated in a dose-dependent manner by the addition of Al(3+), increasing the antioxidative activity of the mixture of anthocyanins.

Thermal degradation of anthocyanins from purple potato (cv. Purple Majesty) and impact on antioxidant capacity

Degradation parameters of purified anthocyanins from purple-fleshed potato (cv. Purple Majesty) heated at high temperatures (100-150 °C) were determined. Purified anthocyanins, prepared by removing salts, sugars, and colorless nonanthocyanin phenolics from the crude extract, were monitored and quantified using HPLC and spectrophotometry for heat-induced degradation products. Separation of colorless phenolics from the anthocyanins was confirmed using HPLC at two wavelengths, 280 and 520 nm. The degradation kinetics of purified anthocyanins followed a first-order reaction with reaction rate constants (k values) of 0.0262-0.2855 min(-1), an activation energy of 72.89 kJ/mol, thermal death times (D values) of 8.06-8789 min, and a z value of 47.84 °C over the temperature range of 100-150 °C. The enthalpy and entropy of activation were 59.97 kJ/mol and -116.46 J/mol·K, respectively. The antioxidant capacity in the purified anthocyanins, measured by DPPH and ABTS assays, was increased after the thermal treatment, indicating antioxidant activities of degradation products in the samples.