Comparative study of the phenolics,antioxidant and metagenomic composition of novel soy whey-based beverages produced using three different water kefir microbiota

Water kefir microbiota was used to develop novel soy whey-based beverages that have antioxidant activity. In the present study, comparative phenolics, antioxidant and metagenomic composition of the soy whey beverages fermented using three different water kefir microbiota, named WKFS-A, WKFS-B and WKFS-C were investigated. WKFS-B beverage had the highest concentrations of isoflavone aglycones (208.73 ± 2.78 mg L⁻¹) and phenolic acids (132.33 ± 3.41 mg L⁻¹) compared with WKFS-A (193.88 ± 1.15 mg L⁻¹) and (91.73 ± 2.34 mg L⁻¹) and WKFS-C (160.63 ± 1.76 mg L⁻¹) and (97.13 ± 2.63 mg L⁻¹), respectively. The WKFS-B also showed higher DPPH and ABTS radical scavenging activity and ferric reducing antioxidant power compared with WKFS-A and WKFS-C beverages. Microbial species diversity index analysis showed that a higher concentration of isoflavone aglycones, phenolic acids and increased antioxidant activity in the WKFS-B beverage correlates with the higher relative abundance of Lactobacillus genus. This study thus revealed that Lactobacillus dominated water kefir microbiota produces soy whey beverages with high phenolic acids, isoflavone aglycones and antioxidant activity.     

Antioxidant potential of extracts from peels and stems of yellow-fleshed and white cassava varieties

This study focused on the exploration of the potentials of extracting antioxidants from peels and stems of yellow-fleshed and white cassava varieties. The effect of particle size (0.2 and 0.5 mm) and variety on the phenolic content and antioxidant activity was assessed. The peels of the yellow-fleshed cassava variety with a particle size of 0.2 mm showed the highest phenolic content with 681.5 GAE mg 100 g⁻¹ and antioxidant activity of 19% and 425 μM TE g⁻¹ dry matter using DPPH and FRAP assays respectively. The stems of the white cassava with a particle size of 0.2 mm exhibited high phenolic content (442.4 GAE mg 100 g⁻¹) and antioxidant activity of 12.8% and 234 μM TE g⁻¹, better than the stem of the yellow-fleshed cassava. These results indicate that phenolic and antioxidant extractions were influenced by variety, the plant parts and particle size for the antioxidant assays.     

Evaluation of antioxidant activity of olive leaf extract obtained by ultrasound-assisted extraction and their antimicrobial activity against bacterial pathogens from food

The aim of the present study was to evaluate and compare the phenolic content and antioxidant and antimicrobial properties of olive leaf extracts obtained by ultrasound-assisted extraction (UAE) and conventional extraction (CSE). UAE of olive leaf extracts yielded a higher total phenolic content (TPC) and total flavonoid content (TFC) of 14.31% and 19.50%, respectively. Higher antioxidant activities were found from the extracts prepared with UAE (for 18.5%, 12.5%, 10.9% and 17.6% higher determined by DPPH, ABTS, FRAP and CUPRAC methods, respectively). Good antibacterial inhibitory activity (as MIC and MBC) was observed against both Y. enterocolitica and S. aureus (1.40 ± 0.40 mg mL⁻¹ and 4.00 ± 1.60 mg mL⁻¹, respectively) with the extract prepared with UAE. In conclusion, olive leaf extracts prepared with UAE exhibited higher antioxidant and antimicrobial activities against common food-borne pathogens than CSE extracts and thus could be beneficial in ensuring food quality and food safety.     

Release of angiotensin converting enzyme-inhibitory peptides during in vitro gastro-intestinal digestion of camel milk

Angiotensin-converting enzyme (ACE)-inhibitory peptides released from camel milk after simulated gastro-intestinal digestion were identified. The hydrolysis degree increased during digestion. The highest ACE-inhibitory activity was found in the post-pancreatic <3 kDa fraction. Peptides responsible for the biological activity were isolated by reversed-phase high-performance liquid chromatography and identified by mass spectrometry. Among the identified sequences, 17 were identical to known bioactive peptides with ACE-inhibitory activity. Based on previous structure–activity relationship studies, the sequence of some peptides allowed us to anticipate the presence of biological activities. The anti-hypertensive tripeptide isoleucine-proline-proline (IPP) was identified and quantified in digested camel milk. The amount of released IPP was 2.56 ± 0.15 mg L⁻¹ of milk. For the first time, we showed that IPP is released during the gastro-intestinal digestion of camel milk κ-casein. This research provides the basis to increase the exploitation of the health benefits of camel milk.     

Bioactive compounds and antioxidant activities of Brazilian hop (Humulus lupulus L.) extracts

Bioactive compounds from Brazilian hop (Humulus lupulus L.) cultivars were extracted by ultrasound and their phenolic profile compared with commercial hop from the USA. The most effective extraction conditions (solution of ethanol 49%, at 52 °C and a solid/liquid ratio of 1 g per 34 mL) for the total phenolic compounds (TPC) were determined using a Central Composite Rotatable Design. The Brazilian hop showed higher content of TPC (33.93 ± 0.67 mg GAE g⁻¹), total flavonoids (54.47 ± 0.10 mg QE g⁻¹) and higher antioxidant activity (ABTS: EC₅₀ 21.29 ± 1.36 μL mL⁻¹; DPPH: EC₅₀ 3.91 ± 0.17 μL mL⁻¹) when compared with the USA hop. The main phenolic compounds present in the extracts were the flavonoids isoquercitrin and quercetin. The antioxidant properties of the Brazilian hop extract had not been reported yet in the literature for this raw material, thus showing potential to be incorporated in polymeric films used as active packaging.     

Extract of Salicornia europaea in fresh pasta to enhance phenolic compounds and antioxidant activity

Extract from Salicornia europaea was added to durum wheat fresh pasta. Sensory properties, cooking quality, microbiological stability, content in bioactive compounds and antioxidant activity, before and after pasta digestion were studied. The extract was obtained by ultrasound-assisted extraction. From the technological point of view the extract did not affect pasta dough and the cooking parameters and sensory properties of the enriched samples were found similar to the control pasta. No antimicrobial effect was exerted by the extract. From the chemical point of view interesting findings were recorded for pasta before and after digestion. Specifically, data of bioaccessible fraction of digested sample showed a significantly higher amount of total phenols and flavonoid content (11.52 mg gallic acid g⁻¹ and 0.55 mg quercetin g⁻¹ respectively) than digested control pasta (9.54 mg gallic acid g⁻¹ and 0.23 mg quercetin g⁻¹ respectively). The antioxidant activity of enriched sample also increased compared to the control pasta (6.20 vs. 2.50 μmoles FeSO₄ g⁻¹).     

Pleurotusostreatus and Agaricus subrufescens: investigation of chemical composition and antioxidant properties of these mushrooms cultivated with different handmade and commercial supplements

In this study, the chemical composition, total phenolic content and antioxidant activity (DPPH, ORAC and FRAP assays) of A. subrufescens and P. ostreatus, cultivated with handmade and commercials supplements, were compared. Additionally, the compounds ergosterol, saccharopine, and hexitol were identified in A. subrufescens by HPLC-MS/MS. The antioxidant compound p-coumaric acid and dihexoses was found in both mushroom species. A. subrufescens presented higher total phenolic content (73.8 ± 0.6 mg GAE 100 g⁻¹) and antioxidant activity than P. ostreatus (16.6 ± 0.5 mg GAE 100 g⁻¹). The handmade supplement based on the waste of noble grains presented statistically similar phenolic content to the mushrooms cultivated with commercial ones Spawn Mate II SE (86.1 ± 1.4 and 92.9 ± 0.3 mg GAE 100 g⁻¹, respectively). Therefore, the results support the use of handmade supplements based on agro-wastes as a viable alternative to the use of high-cost commercial ones.     

Production,iron analysis and consumer perception of functional Thai Sinlek iron rice (Oryza sativa) drink

We produced the iron rice (IR) drink, determined the relevant chemical composition and antioxidant activity and tested the consumers’ degree of satisfaction. IR grains were digested with α-amylase and analysed chemical composition and antioxidant activity, while the hydrolysate (pH 4.0) and flavouring agents were added for final preparation of the IR drink. The IR hydrolysate contained a total iron content of 13.9 mg g⁻¹, a total phenolic content of 1.33 ± 0.07 mg gallic acid equivalent g⁻¹ and γ-oryzanol of 70.12 ± 2.7 mg kg⁻¹ rice grain, all of which inhibited the generation of free radicals in a concentration-dependent manner. The IR drink was composed of flavonoids and phenolic acids for which kaempferol was predominant. The members of all three groups of elderly subjects who consumed the low-dose IR (1.47 mg iron/100 mL), high-dose IR (2.74 mg iron/100 mL) and white rice (WR; 0.5 mg iron/100 mL) drinks expressed satisfaction and interest with the beverages at 91.2%, 100% and 88.9%, respectively. In terms of sensory evaluation, the low-dose IR drink revealed a higher acceptance rating than high-dose IR and WR (P < 0.05). Notably, the Sinlek rice drink was abundant with iron, anti-oxidative phenolics and γ-oryzanol, for which consumers expressed an overall degree of acceptance (8.1 ± 1.1).     

Solvent extraction and in vitro simulated gastrointestinal digestion of phenolic compounds from purple sweet potato

The total content of phenolic compounds in purple sweet potato (PSP) was determined and the release of such compounds from PSP in gastrointestinal digestion was studied in vitro. The extraction conditions for the maximum recovery of free phenol (FP) and bound phenol (BP) from PSP were determined by response surface methodology (RSM). The maximum recovery of FPPSP was 14.16 ± 0.87 mg GAE per g short for dry weight (DW), which was obtained using 60% (v/v) ethanol maceration with a liquid–solid ratio of 57.21:1 (mL g⁻¹) at 51.93 °C for 2.12 h. The maximum recovery for BPPSP was 7.54 mg GAE per g DW, which was obtained upon hydrolysis with 1.87 mol L⁻¹ NaOH at a liquid–solid ratio of 35.93:1 (mL g⁻¹) for 4.74 h. The maximum phenolic content was released after 1 and 2 h for the in vitro gastric and intestinal digestion respectively. The release of the phenolics was promoted by pepsin and gastric acid during gastric digestion, while it was further promoted by trypsin during intestinal digestion.     

Extraction of antioxidant and antimicrobial compounds from Inga marginata Willd bark and pulp using different extraction techniques and phytochemical characterization

This study aimed to identify the least aggressive and highest yield extraction method to obtain bioactive compounds from Inga marginata Willd fruits, determine the chemical components, and evaluate the extracts’' antimicrobial and cytotoxic activity. The extraction efficiency was expressed by the total phenolic and total flavonoid content and antioxidant activity (DPPH, IC₅₀, and ORAC) using conventional, ultrasound, and microwave-assisted extraction. The highest bioactive compound content was achieved using 5 min at 60 °C for total phenolic content (214.98 mg GAE g⁻¹), total flavonoid content (22.90 mg EQ g⁻¹), DPPH (45.98 μmol TEAC g⁻¹), inhibitory capacity (0.80 mg mL⁻¹), and ORAC (167.25 μmol Trolox g⁻¹) using ultrasonic extraction, and the extract inhibited the growth of all microorganisms tested. Thirteen chemical compounds were determined by ESI-ToF-MS, confirming the high phytochemical capacity of the extract. Lastly, the Inga extract showed no cytotoxicity at the concentrations used.     

Antioxidant and anti-inflammatory activities of ethyl acetate extracts of chub mackerel (Scomber colias): a thorough seasonal evaluation

The seasonal variation of key bioactivities in ethyl acetate extracts of chub mackerel (Scomber colias), an underutilised fish species, was evaluated through a complete monthly sampling. The phenolic content had a seasonal variation, ranging from 39 ± 5 mg GAE/100 g ww (February) to 340 ± 6 mg GAE/100 g ww (October). Ferric reducing antioxidant power (FRAP) increased from 1.3 ± 0.4 μmol Fe²⁺ Eq/g ww (January) to 10.3 ± 0.1 μmol Fe²⁺ Eq/g ww (September). ABTS had no antioxidant activity between June and December, being the highest value in February, 64.3 ± 6.3 μmol Trolox Eq/100 g ww. For phenolic content and FRAP, there was a strong seasonality, which was similar to that of the lipid content. Therefore, correlations were high, being R² 0.95 for lipid vs. phenolic contents. Anti-inflammatory activity did not show large changes throughout most part of the year, remaining high in the 70–80% of COX-2 inhibition. This finding and the seasonality of the antioxidant properties warrant further research.     

The effect of simulated digestion on the composition of phenolic compounds and antioxidant activities in lychee pulp of different cultivars

Simulated gastric fluid (SGF) and intestinal fluid (SIF) digestion were used to evaluate the effects of digestion on the composition of phenolic compounds and antioxidant capacities of the pulp of six lychee cultivars. Caffeic acid, ferulic acid, procyanidin B2, epicatechin, A-type procyanidin trimer, procyanidin A2, quercetin-3-rutinose-7-rhamnoside, rutin and isoquercitrin were quantified using HPLC-DAD. Lychee pulp had high concentrations of procyanidin B2 (0.30~15.53 mg g⁻¹), procyanidin A2 (0.29~0.52 mg g⁻¹) and quercetin-3-rutinose-7-rhamnoside (0.16~0.45 mg g⁻¹). SGF and SIF Digestion, which significantly decreased the concentration of procyanidin B2, epicatechin and quercetin-3-rutinose-7-rhamnoside. But observably increased the concentration of procyanidin A2. Compared with deionized water treatment (DW), the total phenolic content (TPC) and total flavonoid content (TFC) of different lychee pulps significantly increased after SGF and SIF digestion. After SGF digestion, the ferric ion reducing antioxidant power (FRAP) of lychee pulps increased while the ABTS+ free radical scavenging ability (ABTS) had a slight decline. This shows that simulated digestion improves the bioactive component and antioxidant activity of different varieties of lychee pulp.     

A novel antioxidant source: evaluation of in vitro bioaccessibility,antioxidant activity and polyphenol profile of phenolic extract from black radish peel wastes (Raphanus sativus L. var. niger) during simulated gastrointestinal digestion

The aim of this study was to evaluate the potency of polyphenolic extract from black radish (Raphanus sativus L. var. niger) root peel waste (PEBRRP) as an antioxidant food additive. PEBRRP was found a powerful antioxidant extract, in which had 172.9 ± 11.5, 462.72 ± 3.05, and 796.51 ± 10.4 mg TE per g dw of total antioxidant capacity (TAC) by CUPRAC, DPPH, and FRAP assays, respectively. The total phenolic content (TPC) and total flavonoid content (TFC) of PEBRRP were found as 305.51 ± 5.2 mg GAE per g dw and 171.58 ± 6.2 mg CAE per g dw, respectively. The ferulic acid (28.02 ± 4.5 mg per g dw) and epicatechin (19.82 ± 3.6 mg per g dw) were identified as the main polyphenols in undigested PEBRRP. The bioaccessibility of total phenolic and total flavonoid compounds of PEBRRP was found approximately 5%, and the antioxidant capacity of bioaccessible PEBRPP fraction was determined 6% in CUPRAC, 36% in DPPH and 47% in FRAP methods.     

Quantification of major camel milk proteins by capillary electrophoresis

Proteins from dromedary camel milk (CM) produced in Europe were separated and quantified by capillary electrophoresis (CE). CE analysis showed that camel milk lacks β-lactoglobulin and consists of high concentration of α-lactalbumin (2.01 ± 0.02 mg mL⁻¹), lactoferrin (1.74 ± 0.06 mg mL⁻¹) and serum albumin (0.46 ± 0.01 mg mL⁻¹). Among caseins, the concentration of β-casein (12.78 ± 0.92 mg mL⁻¹) was found the highest followed by α-casein (2.89 ± 0.29 mg mL⁻¹) while κ-casein represented only minor amount (1.67 ± 0.01 mg mL⁻¹). These results were in agreement with sodium dodecyl sulphate-polyacrylamide gel electrophoresis patterns. Overall, CE offers a quick and reliable method for the determination of major CM proteins, which may be responsible for the many nutritional and health properties of CM.     

Mango (Mangifera indica L.) leaf extracts as ingredient for the formulation of functional beverages with biological activity

The biological activity of mango leaf extracts from different mango varieties was evaluated in terms of total phenolic content, flavonoids, antioxidant activity and inhibition of α-amylase and α-glucosidase enzymes. Leaf extract-based beverages were formulated and evaluated for some physicochemical, microbiological and sensory properties. Results indicated that the extract from 'Tommy Atkins' mango leaves had the highest total phenols content (137.08 mg of GAE g⁻¹) and antioxidant activity (DDPH = 38.26 mg TEAC 100 g⁻¹; ABTS = 59.13 mg TEAC 100 g⁻¹). The beverage formulated with 20% leaf extract presented the highest percentage of antioxidant activity (38.63%) and inhibition of enzymes α-amylase (41.9%) and α-glucosidase (37.53%). All beverages presented a yellow hue and consumers rated it with a degree of liking between 4.8 and 7.3 according to a hedonic scale. Results showed that the biological properties of beverages could be an alternative for the control of free radicals and glucose levels.     

Effect of bioaugmentation on biochemical characterisation and microbial communities in Daqu using Bacillus,Saccharomycopsis and Absidia

Daqu, a saccharifying and fermenting agent for the production of Chinese vinegar and liquor, is manufactured through a spontaneous solid-state fermentation process (SSF). To investigate the influence of bioaugmentation with native microorganisms on Daqu SSF process, physicochemical properties, microbial biomass, volatile compounds and microbial communities were analysed in laboratory-scale Daqu. The results showed that the amylase activity of Daqu enhanced 6.35% ± 0.74% by inoculating Bacillus amyloliquefaciens, Saccharomycopsis fibuligera and Absidia corymbifera. Obviously higher microbial richness was found in the Daqu with bioaugmentation, although the microbial community structure remained relatively stable. Moreover, a total of twenty-two volatile compounds were detected in the mature Daqu. Slightly increase in the content of alcohols was found in the enhanced group by fungal inoculation, including ethanol (46.58 ± 1.36 mg kg⁻¹), isobutanol (0.19 ± 0.04 mg kg⁻¹) and isoamyl alcohol (1.55 ± 0.13 mg kg⁻¹). This study demonstrated that bioaugmentation had a positive effect on the amylase activity, main volatile compounds and microbial community richness.     

Effect of amino acids on Maillard reaction product formation and total antioxidant capacity in white pan bread

Maillard reaction products (MRPs) can be an important dietary antioxidant source. Bread is the most popular bakery product; however, limited information is available on the antioxidant activities of MRPs generated during bread-baking. This paper reports the effect of different amino acids on bread properties, melanoidin formation and antioxidant activities. Totally six amino acids at four different levels were evaluated. Increasing the amount of amino acid led to darker bread crust, higher melanoidin content and stronger antioxidant activity. Among the six amino acids, bread with glycine had the highest melanoidin content and ABTS radical scavenging activity up to 1079.77 ± 8.43 μmol TE mg⁻¹. Bread with lysine had the highest DPPH radical scavenging activity up to 281.97 ± 10.52 μmol TE mg⁻¹. Bread with alanine had the highest crust metal chelating activity compared with others. Adding certain dietary amino acids is a potential approach to enhance the antioxidant capacity of bread products.     

Oxidative enzymes and functional quality of minimally processed grape berries sanitised with ozonated water

Thompson Seedless (TS) and Black (BS) grapes sanitised with 2, 4, 6, 8 mg L^?1 O₃ or NaOCl (100 mg L^?1) were stored 21 days at 5 °C. Ozonated water stimulated the respiration rate, especially after 5 days of storage, and increased superoxide dismutase and catalase activity compared to NaOCl‐sanitised grapes. Total polyphenol content (TPC) was 23–50% higher in TS and 18.5–28% higher in BS samples sanitised with ozonated water. Twofold higher total antioxidant capacity (TAC) was registered in TS at all of the evaluated O₃ doses while the doses of 6 and 8 mg L^?1 increased TAC by 19–30% in BS. The use of ozonated water as a sanitising method, especially at 6 and 8 mg L^?1 doses, improved the functional quality and maintained low microbial counts on fresh‐cut grapes being a good alternative for the industry.     

Changes in phenolics, γ-aminobutyric acid content and antioxidant,antihypertensive and hypoglycaemic properties during ale white sorghum (Sorghum bicolor (L.) Moench) brewing process

Effects of white sorghum brewing process on free amino-acids, γ-aminobutyric acid (GABA), phenolics and bioactivity, including antioxidant (by ABTS⁺ and reducing power, RP, methods), antihypertensive (angiotensin converting enzyme-I, ACE-I inhibition assay), and hypoglycaemic activity (α-glucosidase inhibition assay) were evaluated. From the wort to the beer, free amino acids decreased, but GABA and phenolics increased significantly, positively modifying the bioactive potential. ABTS and α-glucosidase inhibition activity correlated positively with at least one of the phenolic acids evaluated. Ale white sorghum beer presented high content of GABA (7.8 mg L⁻¹), phenolics (40.7 mg total phenolic acids L⁻¹), antioxidant activity (9.14 mmol Trolox equivalent L⁻¹, and 48.8 mmol ascorbic acid equivalent L⁻¹, for ABTS⁺ and RP, respectively), and exhibit ACE-I inhibition (1.0 μg captopril equivalent L⁻¹) and α-glucosidase inhibition (34.5 mg acarbose equivalent L⁻¹) activities. The level of bioactive compounds and its low ethanol content (2.3%), make beer obtained from malted white sorghum a potential functional beverage.     

Evaluation of furosine,lactulose and acid-soluble β-lactoglobulin as time temperature integrators for whipping cream samples at retail in Austria

Three heat load indicators, i.e., furosine, lactulose and acid-soluble β-lactoglobulin, were determined in whipping cream samples purchased from Austrian market (n = 33), as well as commercial samples obtained directly from one Austrian dairy company (one brand, n = 25). Furosine contents were 47.8 ± 14.0, 72.2 ± 36.6, and 172.5 ± 17.7 mg 100 g⁻¹ protein, and β-lactoglobulin contents were 143 ± 91, 195 ± 150, and 89 ± 31 mg L⁻¹ for retailed pasteurised, extended shelf life (ESL), and ultra-high temperature (UHT) cream samples, respectively. Lactulose concentrations (analysed enzymatically) were 29 ± 10, 56 ± 41, and 201 ± 24 mg L⁻¹ for pasteurised, ESL and UHT cream samples, respectively. Linear correlation obtained for furosine and lactulose concentrations indicated that these indicators can reliably assess the heat load of pasteurised, ESL and UHT cream samples, whereas β-lactoglobulin was definitely not appropriate to discriminate between these heating categories.