Polyphenol bioaccessibility and antioxidant properties of in vitro digested spray-dried thermally-treated skimmed goat milk enriched with pollen

Interactions between polyphenols and polysaccharides/proteins: Mechanisms, effect factors, and physicochemical and functional properties: A review

Polyphenols have attracted much attention in the food industry and nutrition because of their unique biological activities. However, the health benefits of polyphenols are compromised due to their structural instability and sensitivity to the external environment. The interaction between polyphenols and polysaccharides/proteins largely determines the stability and functional characteristics of polyphenols in food processing and storage. Hence, this topic has attracted widespread attention in recent years. This review initially outlines the basic properties of polyphenols and their applications in food. Subsequently, the interaction mechanisms between polyphenols and polysaccharides/proteins are discussed in detail including non-covalent bonding, covalent modification, and conformational changes. These interactions can display profound impacts on the nutritional value, taste, stability, and safety of food. Additionally, this article also systematically reviews the influencing factors (type, concentration, temperature, pH, and other factors) of interaction between polyphenols and proteins/polysaccharides. Finally, this paper also summarizes systematically the effects of the interaction between polyphenols and polysaccharides/proteins on the physicochemical and functional properties of polyphenols/proteins. The findings provide prospects for the application of composite materials in food preservation, functional food development, and nanocarrier development, which can provide theoretical references for the in-depth development of polyphenols in the food industry.

Goat's Skim Milk Enriched with Agrocybe aegerita (V. Brig.) Vizzini Mushroom Extract: Optimization, Physico-Chemical Characterization, and Evaluation of Techno-Functional, Biological and Antimicrobial Properties

The aim of this study was to develop a novel functional ingredient-goat's skim milk enriched with Agrocybe aegerita (V. Brig.) Vizzini mushroom extract (ME/M)-using Central Composite Design (CCD). The optimized ME/M ingredient was evaluated for its physico-chemical, techno-functional, biological, and antimicrobial properties. Physico-chemical properties were analyzed using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy, Scanning Electron Microscopy (SEM), and Dynamic Light Scattering (DLS). The ingredient exhibited a polymodal particle size distribution and contained glucans, along with a newly formed polypeptide resulting from the selective cleavage of goat milk proteins. A 0.1% ME/M solution demonstrated good emulsifying and foaming properties. Additionally, ME/M showed strong antiproliferative effects on human cancer cell lines, particularly Caco-2 (colorectal) and MCF7 (breast) cancer cells. The ingredient also promoted HaCaT cell growth without cytotoxic effects, suggesting its safety and potential wound-healing properties. Furthermore, the addition of ME/M to HaCaT cells inoculated with Staphylococcus aureus resulted in reduced IL-6 levels compared to the control (without ME/M), indicating a dose-dependent anti-inflammatory effect. The optimized ME/M ingredient also exhibited antibacterial, antifungal, anticandidal, and antibiofilm activity in one-fourth of MIC. These findings suggest that the formulated ME/M ingredient has strong potential for use in the development of functional foods offering both desirable techno-functional properties and bioactive benefits.

The Bioaccessibility of Grape-Derived Phenolic Compounds: An Overview

Grape-derived phenolic compounds possess many health benefits, but their biological effectiveness and their effects on human health depend directly on bioaccessibility. Different physiological conditions, interactions with food compounds (proteins, lipids, and carbohydrates), and/or microbial transformations affect the solubilization and stability of phenolic compounds, thus altering their bioaccessibility and biological activity. Previously published review articles on grape-derived phenolic compounds have focused on characterization, transformation during winemaking, various applications, and health benefits, but the literature lacks a comprehensive overview of the bioaccessibility of these compounds during gastrointestinal digestion. In this context, models of gastrointestinal digestion and factors affecting the bioaccessibility of phenolic compounds were considered to understand the behavior of grape-derived phenolic compounds during digestion in the absence or presence of different food matrices. Finally, this review should enable the development of novel food products with targeted bioaccessibility of grape-derived phenolic compounds.

Screening and evaluation of novel DPP-IV inhibitory peptides in goat milk based on molecular docking and molecular dynamics simulation

Virtual screening techniques have gained much attention as a means of studying bioactive peptides. This study aimed to screen DPP-IV inhibitor peptides in goat milk after simulated digestion in vitro combined with molecular docking and dynamics simulations. By evaluating the docking energy and active sites, and by analyzing RMSD, RMSF, and Rg values, two novel peptides, GPFPLL and LPYPY, were successfully screened and identified. GPFPLL and LPYPY were found to exhibit high inhibitory activity against DPP-IV (IC50 of 130.68 ± 10.38 μM and 179.52 ± 18.89 μM, respectively). Both GPFPLL and LPYPY stably bound to S1 and S1' in DPP-IV, and both demonstrated competitive inhibition of DPP-IV. The inhibition of DPP-IV by GPFPLL and LPYPY after in vitro digestion reached 31.90 % ± 1.80 % and 39.37 % ± 0.90 %, respectively. In a Caco-2 cell experiment, GPFPLL and LPYPY exhibited significant inhibition of DPP-IV, reaching 46.53 % ± 3.48 % and 65.98 % ± 2.87 %, respectively, when the concentration of each peptide was 2 mg/mL. The results of this study suggest that using molecular docking and dynamics simulations to screen novel peptides is an effective approach, and the identified peptides GPFPLL and LPYPY show potential for diabetes management.

Goat's Milk Powder Enriched with Red (Lycium barbarum L.) and Black (Lycium ruthenicum Murray) Goji Berry Extracts: Chemical Characterization, Antioxidant Properties, and Prebiotic Activity

The current trend in food innovations includes developing products containing plant ingredients or extracts rich in bioactive compounds. This study aimed to prepare and characterize skimmed thermally treated goat's milk powders enriched with lyophilized fruit extracts of Lycium ruthenicum Murray (GMLR) and Lycium barbarum L. (GMLB). Proximate analysis, ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS), Fourier transform infrared spectroscopy using attenuated total reflection (FTIR-ATR), and electrophoretic analysis were assessed. Total phenolic content (TPC), total protein content, and antioxidant properties of enriched goat milk powders were determined spectrophotometrically, and prebiotic potential was evaluated by the broth microdilution method. A total of 25 phenolic compounds and 18 phenylamides were detected in the enriched goat milk powders. Electrophoretic analysis showed the absence of proteolysis in the prepared powders. The GMLR showed the highest TPC and displayed a ferric ion-reducing power, probably contributed by anthocyanins and some phenylamides. GMLR and GMLB had higher ABTS radical scavenging activity but lower ferrous ion-chelating capacity than control goat's milk powder. GMLB and GMLR in a dose-dependent manner (0.3-5 mg/mL) showed a growth-promoting effect on probiotic strains. In summary, prepared goji/goat milk powders, primarily GMLR, might be used as prebiotic supplements or functional food additives.

Enzyme Inhibitory, Physicochemical, and Phytochemical Properties and Botanical Sources of Honey, Bee Pollen, Bee Bread, and Propolis Obtained from the Same Apiary

Bee products are an important source of nutrients and bioactive phytochemicals. This study aimed to determine the chemical composition (proximate composition, general phytochemical composition, sugar, and phenolic profiles) of four different products (honey, bee pollen, bee bread, and propolis), obtained from the same apiary, as well as to assess their biological activity through antioxidant and enzyme inhibition assays (α-amylase, α-glucosidase, lipase, AchE, neuraminidase, angiotensin-converting enzyme, urease, trypsin, tyrosinase, carbonic anhydrase, thioredoxin reductase, adenosine deaminase). Clear differences were observed among the samples in terms of both chemical composition and biological activity. The analysis revealed that bee pollen exhibited the highest carbohydrate content (87.9%), while propolis was identified as the richest source of phenolic compounds (14,858.9 mg/kg) among the analyzed samples. Propolis exhibited the highest biological activity in all applied antioxidant assays (CUPRAC, DPPH•, and ABTS•+) and in most enzyme inhibition assays. Notably, the α-glucosidase inhibition activity of propolis was comparable to that of the reference standard. In addition, honey exhibited remarkable trypsin inhibition, also comparable to the applied standard. These findings highlight the diverse bioactivities of hive products, which could play a key role in promoting health and preventing diseases.

Effect and mechanisms of thermal sterilization methods on the in vitro phenolic bioaccessibility of rose tea with milk

Rose polyphenols, key functional components in roses, require adequate bioaccessibility for their health benefits, subject to influence by food components and processing. Investigating the impact of various thermal sterilization methods on the bioaccessibility of rose polyphenols in rose tea with milk and the underlying mechanisms, our findings indicated a significant increase in bioaccessibility following treatment at 85 °C/30 min. Conversely, 121 °C/15 min treatment decreased bioaccessibility. Examining the interaction between β-casein in milk and rose polyphenols under different sterilization conditions, SEM and particle size analysis revealed binding, with fluorescence spectroscopy indicating non-covalent bonds. Binding forces followed the order 121 °C > 85 °C > 25 °C. Notably, at 85 °C, non-covalent binding improved polyphenol bioaccessibility, while the intensified binding at 121 °C decreased it. SDS-PAGE and amino acid analysis confirmed no covalent bond. This study establishes a theoretical basis for selecting thermal sterilization temperatures for milk-flower combinations, considering polyphenol bioaccessibility.

Unlocking Quercetin's Neuroprotective Potential: A Focus on Bee-Collected Pollen

In the quest to evade side effects associated with synthetic drugs, mankind is continually exploring natural sources. In recent decades, neurodegenerative disorders (NDDs) have surged dramatically compared to other human diseases. Flavonoids, naturally occurring compounds, have emerged as potential preventers of NDD development. Notably, quercetin and its derivatives demonstrated excellent antioxidant properties in the fight against NDDs. Recognizing bee-collected pollen (BP) as a well-established excellent source of quercetin and its derivatives, this review seeks to consolidate available data on the prevalence of this flavonoid in BP, contingent upon its botanical and geographical origins. It aims to advocate for BP as a superb natural source of "drugs" that could serve as preventative measures against NDDs. Examination of numerous published articles, detailing the phenolic profile of BP, suggests that it can be a great source of quercetin, with an average range of up to 1000 mg/kg. In addition to quercetin, 24 derivatives (with rutin being the most predominant) have been identified. Theoretical calculations, based on the recommended dietary intake for quercetin, indicate that BP can fulfil from 0.1 to over 100 % of the requirement, depending on BP's origin and bioaccessibility/bioavailability during digestion.

Bioaccessibility and antioxidant capacity of kefir-based smoothies fortified with kale and spinach after in vitro gastrointestinal digestion

The kefir-based smoothies with kale and spinach were designed as a ready-to-drink and innovative functional snack. Microbiological, physicochemical, as well as pre- and postgastrointestinal total antioxidant capacity (TAC; CUPRAC, DPPH, and FRAP) analyses were conducted. It was determined that the kefir-based smoothies with vegetables had higher ash, carbohydrate, and dietary fiber values. Fructose and glucose contents of smoothy with kale were high, while smoothy with spinach included high sucrose and maltose. The microbiology results revealed that kefir-based vegetable smoothies had minimum Lactobacillaceae viability (>log 7 cfu g-1) for the required functional effect after 14-day storage. Moreover, the addition of kale significantly increased (p < .01) the level of initial TAC (CUPRAC, DPPH, and FRAP) and total phenolic content (TPC) values. After in vitro gastric digestion analysis, smoothie with spinach demonstrated higher TAC and TPC values and the control sample had higher TAC and TPC values compared with a predigestion step. It was found that in vitro intestinal DPPH values were higher for the sample with spinach samples, while the sample with kale had the highest FRAP values. It was also found that the bioaccessibility indexes of plain kefir were determined to be the highest in both in vitro gastric and intestinal procedures. The present study provided novel insights into the in vitro digestion properties of kefir fortified with vegetables. Nevertheless, further studies are needed to identify the functional properties of the milk and plant matrices mixture using in vitro and in vivo trials.

Changes in phenolic profile and anti-inflammatory activity of Baccharis beebread during gastrointestinal digestion/intestinal permeability in vitro

Knowledge about the fate of beebread bioactive compounds throughout the human gastrointestinal tract are scarce. The present study aimed at assessing the effects of gastrointestinal digestion followed by intestinal permeability in vitro on phenolic profile and anti-inflammatory activity of Baccharis beebread. Palynological analysis confirmed the beebread is predominantly composed by pollen grains from Baccharis species, which are endemic in south and southeast Brazil. Flavonols and phenylamides were found in beebread hydroalcoholic extract by HPLC-ESI-QTOF-MS analysis. Moreover, simulated digestion lead to compounds' breakage, releasing both aglycones from glycosylated flavonols and p-coumaric acid, but not caffeic acid from phenylamides. Only spermidines crossed the Caco-2 cell monolayer, possibly due to spermine oxidation. Free p-coumaric acid was released after digestion, and epithelial transport. Concomitantly, NF-κΒ activation and TNF-α level was decreased by beebread even after Caco-2 transport, which indicates spermidines conjugated with p-coumaric acid may be bioavailable compounds with anti-inflammatory activity.

Characterization of the Effect of a Novel Production Technique for 'Not from Concentrate' Pear and Apple Juices on the Composition of Phenolic Compounds

The consumption of 'not-from-concentrate' (NFC) fruit juices can be a convenient and enjoyable way to incorporate the nutritional benefits and flavors of fruits into one's diet. This study will focus on the effect of production of juices from apple and pear fruits, by using centrifugal decanter and tangential filtration, on the profile of polyphenols as a valuable source of bioactive compounds. Likewise, by-products from the juice industry were characterized in order to understand the high-value-added potential based on their composition of polyphenols. Briefly, apple and apple juice showed great contents of chlorogenic acid (0.990 ± 0.021 mg/g of DW), the dihydrochalcone phloridzin (1.041 ± 0.062 mg/g of DW), procyanidins (0.733 ± 0.121 mg/g of DW) and quercetin derivatives (1.501 ± 0.192 mg/g of DW). Likewise, the most abundant compounds in pear and pear juices were chlorogenic acid (0.917 ± 0.021 mg/g of DW), caffeoylquinic acid (0.180 ± 0.029 mg/g of DW), procyanidins (0.255 ± 0.016 mg/g of DW) and quercetin derivatives (0.181 ± 0.004 mg/g of DW). Both temperature and tangential speed affect the amount of phenolic compounds in fruit juices, highlighting the need to control the technological process to obtain a more nutritious/healthier beverage. Overall, NFC juices arise as a better option when compared with concentrated juices. Furthermore, the higher yield of phenolic compounds found in fruit pomace clearly open new ways for upcycling this fruit by-product as a high-value-added ingredient.

Preparation, identification, and inhibitory mechanism of dipeptidyl peptidase IV inhibitory peptides from goat milk whey protein

This study explores potential hypoglycemic mechanisms by preparing and identifying novel dipeptidyl peptidase IV (DPP-IV) inhibitory peptides from goat milk (GM) whey protein. Papain was used to hydrolyze the GM whey protein. After purification by ultrafiltration, the Sephadex column, and preparative RP-HPLC, the peptide inhibited DPP-IV, α-glucosidase, and α-amylase with IC50 of 0.34, 0.37, and 0.72 mg/mL, respectively. To further explore the inhibitory mechanism of peptides on DPP-IV, SPPEFLR, LDADGSY, YPVEPFT, and FNPTY were identified and synthesized for the first time, with IC50 values of 56.22, 52.16, 175.7, and 62.32 µM, respectively. Molecular docking and dynamics results show that SPPEFLR, LDADGSY, and FNPTY bind more tightly to the active pocket of DPP-IV, which was consistent with the in vitro activity. Furthermore, the first three N-terminals of SPPEFLR and FNPTY peptides exhibit proline characteristics and competitively inhibit DPP-IV. Notably, the first N-terminal leucine of LDADGSY may play a key role in inhibiting DPP-IV.

Monofloral Corn Poppy Bee-Collected Pollen-A Detailed Insight into Its Phytochemical Composition and Antioxidant Properties

The aim of this study was to compile a detailed phytochemical profile and assess the antioxidant properties of bee-collected pollen (PBP) obtained from corn poppy (Papaver rhoeas L.) plants. To achieve this, a lipid fraction was prepared for quantifying fatty acids using GC-FID. Extractable and alkaline-hydrolysable PBP fractions (obtained from a defatted sample) were used to determine the qualitative and quantitative profiles of phenolic compounds, phenylamides and alkaloids using UHPLC/Q-ToF-MS. Additionally, various spectrophotometric assays (TAC, FRP, CUPRAC, DPPH^⦁) were conducted to evaluate the antioxidant properties. Phenolic compounds were more present in the extractable fraction than in the alkaline-hydrolysable fraction. Luteolin was the predominant compound in the extractable fraction, followed by tricetin and various derivatives of kaempferol. This study presents one of the first reports on the quantification of tricetin aglycone outside the Myrtaceae plant family. The alkaline-hydrolysable fraction exhibited a different phenolic profile, with a significantly lower amount of phenolics. Kaempferol/derivatives, specific compounds like ferulic and 5-carboxyvanillic acids, and (epi)catechin 3-O-gallate were the predominant compounds in this fraction. Regarding phenylamides, the extractable fraction demonstrated a diverse range of these bioactive compounds, with a notable abundance of different spermine derivatives. In contrast, the hydrolysable fraction contained six spermine derivatives and one spermidine derivative. The examined fractions also revealed the presence of seventeen different alkaloids, belonging to the benzylisoquinoline, berberine and isoquinoline classes. The fatty-acid profile confirmed the prevalence of unsaturated fatty acids. Furthermore, both fractions exhibited significant antioxidant activity, with the extractable fraction showing particularly high activity. Among the assays conducted, the CUPRAC assay highlighted the exceptional ability of PBP's bioactive compounds to reduce cupric ions.

Antioxidant and anti-inflammatory activities of rape bee pollen after fermentation and their correlation with chemical components by ultra-performance liquid chromatography-quadrupole time of flight mass spectrometry-based untargeted metabolomics

As a common food processing technology, microbial fermentation is becoming increasingly popular to promote the bioactivity of materials. This study aims to enhance rape bee pollen bioactivity through fermentation and trace the potential components associated with its bioactivity. The antioxidant and anti-inflammatory activities of unfermented bee pollen and fermented bee pollen were evaluated, and their correlation with differential metabolites was analyzed. The results indicated that fermentation significantly (p < 0.05) improved the antioxidant (>2.3-fold) and anti-inflammatory (>1.36-fold) activities of bee pollen, and increased the contents of total phenolics and flavonoids by 1.99 and 1.53 folds. Moreover, the correlation analysis results indicated that 15 components, including three phenolamides, one flavonoid aglycone, seven fatty acids, three amino acids and one ketone compound, were positively correlated with bee pollen antioxidant and anti-inflammatory activities. These results suggest that fermentation is a promising approach to increase the bioactivity of bee pollen.

Translational Research on Bee Pollen as a Source of Nutrients: A Scoping Review from Bench to Real World

The emphasis on healthy nutrition is gaining a forefront place in current biomedical sciences. Nutritional deficiencies and imbalances have been widely demonstrated to be involved in the genesis and development of many world-scale public health burdens, such as metabolic and cardiovascular diseases. In recent years, bee pollen is emerging as a scientifically validated candidate, which can help diminish conditions through nutritional interventions. This matrix is being extensively studied, and has proven to be a very rich and well-balanced nutrient pool. In this work, we reviewed the available evidence on the interest in bee pollen as a nutrient source. We mainly focused on bee pollen richness in nutrients and its possible roles in the main pathophysiological processes that are directly linked to nutritional imbalances. This scoping review analyzed scientific works published in the last four years, focusing on the clearest inferences and perspectives to translate cumulated experimental and preclinical evidence into clinically relevant insights. The promising uses of bee pollen for malnutrition, digestive health, metabolic disorders, and other bioactivities which could be helpful to readjust homeostasis (as it is also true in the case of anti-inflammatory or anti-oxidant needs), as well as the benefits on cardiovascular diseases, were identified. The current knowledge gaps were identified, along with the practical challenges that hinder the establishment and fructification of these uses. A complete data collection made with a major range of botanical species allows more robust clinical information.

Food nanoemulsions: how simulated gastrointestinal digestion models, nanoemulsion, and food matrix properties affect bioaccessibility of encapsulated bioactive compounds

Food nanoemulsions are known as very effective and excellent carriers for both lipophilic and hydrophilic bioactive compounds (BCs) and have been successfully used for controlled delivery and protection of BCs during gastrointestinal digestion (GID). However, due to sensitive and fragile morphology, BCs-loaded nanoemulsions have different digestion pathways depending on their properties, food matrix properties, and applied models for testing their digestibility and BCs bioaccessibility. Thus, this review gives a critical review of the behavior of encapsulated BCs into food nanoemulsions during each phase of GID in different static and dynamic in vitro digestion models, as well as of the influence of nanoemulsion and food matrix properties on BCs bioaccessibility. In the last section, the toxicity and safety of BCs-loaded nanoemulsions evaluated on in vitro and in vivo GID models have also been discussed. Better knowledge of food nanoemulsions' behavior in different models of simulated GI conditions and within different nanoemulsion and food matrix types can help to standardize the protocol for their testing aiming for researchers to compare results and design BCs-loaded nanoemulsions with better performance and higher targeted BCs bioaccessibility.

Effects of Spray Drying, Freeze Drying and Gamma Irradiation on the Antioxidant Activities of Camel and Cow Milk Fractions

This work aimed to establish an integrated approach to investigate the total phenolic content and antioxidant activities of dried skim camel and cow milk and their fractions. The milk fractions were obtained by acid or enzymatic coagulation followed by spray drying (inlet temperature/outlet temperature: 125 ± 2 °C/90 ± 2 °C) or freeze drying (−50 °C, 0.05 mbar) coupled or not to gamma irradiation (at 5, 11, 22 kGy). The results showed that the total phenolic content (measured in gallic acid equivalent, GAE) varied depending on the drying technique. The freeze-drying process corresponded to the highest values of total phenolic compounds, with 247.23 ± 2.08 mg GAE/100 g powder for the β-casein fraction of camel milk (βC CaM) and 621.13 ± 4.16 mg GAE/100 g powder for the β-casein fraction of cow milk (βC CoM). Compared to spray-dried fractions, freeze-dried fractions showed generally higher ferric reducing antioxidant power for both camel milk and cow milk. The highest values of free radical scavenging activity were seen in the spray-dried β-casein fractions of camel milk (βC CaM) and cow milk (βC CoM) and in the freeze-dried acid whey of cow and camel milk (AW CaM and AW CaM). Freeze-dried acid whey (AW CaM and AW CoM) appeared to be less sensitive to gamma irradiation at 5 and 11 kGy.

Biscuits Enriched with Monofloral Bee Pollens: Nutritional Properties, Techno-Functional Parameters, Sensory Profile, and Consumer Preference

Bee pollens are potential functional food ingredients as they contain essential nutrients and a wide range of bioactive compounds. The aim of this study was to investigate the effects of enrichment with monofloral bee pollens on the nutritional properties, techno-functional parameters, sensory profile, and consumer preference of biscuits. Biscuits were prepared according to the AACC-approved method by substituting wheat flour with pollens of rapeseed (Brassica napus L.), phacelia (Phacelia tanacetifolia Benth.) and sunflower (Helianthus annuus L.) at 2%, 5% and 10% levels. The macronutrient composition of the biscuits was determined: crude protein content (Kjeldahl method), crude fat content (Soxhlet extraction), ash content (carbonization), moisture content (drying), carbohydrate content (formula). Their total phenolic content (TPC) and in vitro antioxidant capacity (FRAP, TEAC, DPPH) were determined spectrophotometrically. The colour of the biscuits was measured using a tristimulus-based instrument, and their texture was characterized by using a texture analyser. Sensory profile of biscuits was determined by qualitative descriptive analysis (QDA). The consumer acceptance and purchase intention of the biscuits were also evaluated, based on the responses of 100 consumers. Additionally, an external preference map was created to illustrate the relationship between consumer preference and the sensory profile of the biscuits, and penalty analysis was conducted to identify directions for product development. Phacelia pollen appeared to be the most effective for improving the nutritional quality of biscuits. The addition of phacelia pollen at the 10% substitution level increased the protein content and TPC of the control biscuit by 21% and 145%, respectively. Significant changes (p < 0.05) were also observed regarding the colour and texture of biscuits. The results of the QDA revealed that biscuits containing pollens of different botanical sources have heterogeneous sensory attributes. The biscuit containing sunflower pollen at the 2% substitution level was preferred the most (overall liking = 6.9 ± 1.6), and purchase intentions were also the highest for this product. Based on the results of the present study, it is recommended to use sunflower pollen for developing pollen-enriched foods in the future.

Bioaccessibility of Phenolic Compounds and Antioxidant Properties of Goat-Milk Powder Fortified with Grape-Pomace-Seed Extract after In Vitro Gastrointestinal Digestion

This study deals with the evaluation of the bioaccessibility and antioxidant properties of phenolic compounds from heat-treated skim goat-milk powder fortified with grape-pomace-seed extract, after in vitro gastrointestinal digestion. Ultra-high performance liquid chromatography coupled to diode array detection and mass spectrometry (UHPLC-DAD MS/MS) analysis confirmed the abundant presence of phenolic acids and flavan-3-ols in the grape-pomace-seed extract (SE) and heat-treated skim goat-milk/seed-extract powder (TME). After in vitro digestion of TME powder and recovery of total quantified phenolics, flavan-3-ols and phenolic acids were 18.11%, 24.54%, and 1.17%, respectively. Low recovery of grape-pomace-seed phenolics indicated strong milk protein-phenolic interactions. Electrophoretic analysis of a soluble fraction of digested heat-treated skim goat milk (TM) and TME samples showed the absence of bands originating from milk proteins, indicating their hydrolysis during in vitro gastrointestinal digestion. The digested TME sample had better antioxidant properties in comparison to the digested TM sample (except for the ferrous ion-chelating capacity, FCC), due to the presence of bioaccessible phenolics. Taking into account the contribution of the digestive cocktail, digested TME sample had lower values of total phenolic content (TPC), in vitro phosphomolybdenum reducing capacity (TAC) and ferric reducing power (FRP), compared to the undigested TME sample. These results could be attributed to low recovery of phenolic compounds. TME powder could be a good carrier of phenolics to the colon; thus, TME powder could be a promising ingredient in the formulation of functional food.

EPS-Producing Lactobacillus plantarum MC5 as a Compound Starter Improves Rheology, Texture, and Antioxidant Activity of Yogurt during Storage

This study evaluated the effects of probiotic Lactobacillus plantarum MC5 on the quality, antioxidant activity, and storage stability of yogurt, to determine its possible application as a starter in milk fermentation. Four groups of yogurt were made with different proportions of probiotic L. plantarum MC5 and commercial starters. The yogurt samples’ rheological properties, texture properties, antioxidant activity, storage stability, and exopolysaccharides (EPS) content during storage were determined. The results showed that 2:1 and 1:1 yogurt samples (supplemented with L. plantarum MC5) attained the highest EPS content (982.42 mg/L and 751.71 mg/L) during storage. The apparent viscosity, consistency, cohesiveness, and water holding capacity (WHC) of yogurt samples supplemented with L. plantarum MC5 were significantly higher than those of the control group (p < 0.05). Further evaluation of antioxidant activity revealed that yogurt samples containing MC5 starter significantly increased in DPPH, ABTS, OH, and ferric iron-reducing power. The study also found that adding MC5 can promote the growth of Streptococcus thermophilus. Therefore, yogurt containing L. plantarum MC5 had favorable rheological properties, texture, and health effects. The probiotic MC5 usage in milk fermentation showed adequate potential for industrial application.

Honeybee Pollen From Southern Chile: Phenolic Profile, Antioxidant Capacity, Bioaccessibility, and Inhibition of DNA Damage

Honeybee pollen (HBP) chemical composition is highly variable conforming to the floral and geographical origin of the pollen grains. The beneficial effects and functional properties of the HBP are well-known and have been mainly attributed to their high content of antioxidant polyphenols. In this work, twelve HBPs samples from the Southern region of Chile (X Región de Los Lagos) were characterized for the first time according to their botanical origin, phenolic composition, and antioxidant activity. The in vitro gastrointestinal digestion assay was done to simulate the human upper digestive tract. Selected honeybee pollen extracts (HBPEs) were assessed as bioaccessible fractions during an in vitro gastrointestinal digestion. Contents of phenolic compounds, antioxidant capacity, and recovery index of quercetin, myricetin, and cinnamic acid were monitored in different steps of gastrointestinal digestion. Furthermore, the protective effect of in vitro digested HBP towards DNA damage induced by peroxyl radicals was evaluated. The introduced species Brassica rapa L. (Brassicaceae), Lotus pedunculatus Cav. (Fabaceae), and Ulex europaeus L. (Fabaceae) predominated in all the HBPs analyzed, while the native species Buddleja globosa Hope (Scrophulariaceae), Luma apiculata (DC.) Burret (Myrtaceae), Embothrium coccineum J.R. Forst. & G. Forst. (Proteaceae) and Eucryphia cordifolia Cav. (Cunoniaceae) appeared less frequently. The content of polyphenols and antioxidant capacity in HBPEs achieved full bioaccessibility at the end of the intestinal digestion step. However, results obtained by a state-of-the-art technique (i.e. HPLC-DAD) demonstrated relatively low values of bioaccessible quercetin and cinnamic acid after the digestion process. In contrast, myricetin showed a high bioaccessibility in the intestinal digestion steps. The protective effect of in vitro digested HBP towards DNA damage induced by peroxyl radicals showed promising results (up to 91.2% protection). In conclusion, HBPs from the X Region de Los Lagos are rich sources of phenolic antioxidants that protect DNA from strand breakage. Therefore, the potential of HBPEs in preventing gastric and/or intestinal cancer should be further considered.

Widely targeted metabolomics analysis reveals the effect of fermentation on the chemical composition of bee pollen

Microbial fermentation can break the bee pollen wall. However, the global profiling of bee pollen metabolites under fermentation remains unclear. This study aims to comprehensively elucidate the changes in the composition of bee pollen after microbial fermentation. Ultra-performance liquid chromatography-electron spray ionization-mass spectrometry (UPLC-ESI-MS) based on widely targeted metabolomics analysis was used to compare the chemical composition of unfermented bee pollen (UBP) and fermented bee pollen (FBP). Among the 890 metabolites detected, a total of 668 differential metabolites (classified into 17 categories) were identified between UBP and FBP. Fermentation significantly increased the contents of primary metabolites such as 74 amino acids and derivatives, 42 polyunsaturated fatty acids and 66 organic acids, as well as some secondary metabolites such as 38 phenolic acids, 80 flavone aglycones and 22 phenolamides. The results indicate that fermentation is a promising strategy to improve the nutritional value of bee pollen.

Phytochemical Profile and Antioxidant Properties of Bee-Collected Artichoke (Cynara scolymus) Pollen

The current study intended to determine, for the first time, phenolic and fatty acid profile, antioxidant and certain nutritional properties of monofloral bee-collected artichoke (Cynara scolymus) pollen. Based on UHPLC-DAD MS-MS analysis the main phenolics in extractable fraction were different flavonol glycosides (in particular Isorhamnetin-3-O-glucoside, 49.2 mg/kg of dry weight) while ferulic acid was the predominant phenolic compound (39.4 mg/kg of dry weight) in the alkaline hydrolyzable fraction. Among fatty acids (FAs), results of GC-FID analysis revealed prevalence of unsaturated FAs with cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and oleic acid as the main ones- 28.4% and 24.9%, respectively. Based on the FA composition, nutritional analysis proved that artichoke bee-collected pollen had balanced ω-6 and ω-3 FAs content. To determine the antioxidant properties of pollen, five different assays were applied. It was proved that bioactive compounds in artichoke pollen possessed significant ability to quench DPPH radical as well as ABTS radical cation. In addition, in vitro phosphomolybdenum assay confirmed that artichoke pollen is an excellent source of different antioxidants. Pollen extracts exhibited moderate ferric reducing power as well as low ferrous chelating ability. Some further antioxidant studies (preferably in vivo) should be performed to confirm the observed results.

Skimmed Goat's Milk Powder Enriched with Grape Pomace Seed Extract: Phenolics and Protein Characterization and Antioxidant Properties

The aim of this research was phenolics and protein characterization and antioxidant properties evaluation of skimmed thermally treated goat's milk powder enriched with different concentration of grape pomace seed extract (SE). The dominant phenolics in SE were phenolic acids, flavan-3-ols and procyanidins. Different electrophoretic techniques together with UHPLC-MS/MS analysis revealed the presence of phenolics-protein interactions in the samples, mainly procyanidins with whey protein/caseins complexes. Addition of SE into thermally treated goat's milk significantly improved antioxidant properties of goat's milk such as TAC, FRP, DPPH^• and ABTS^•+ scavenging activity. Gallic acid, catechin, and procyanidins mostly contributed to these activities. The schematic representation of phenolics-casein micelles interactions in thermally treated goat's milk enriched with SE was given. The addition of SE into thermally treated goat's milk can be a promising strategy in food waste recovery and to enhance the beneficial health effects of goat's milk-based functional foods.

Storage Stability of Antioxidant in Milk Products Fermented with Selected Kefir Grain Microflora

The aim of the study was to assess the antioxidant potential of goat’s milk and whey from goat’s milk fermented with selected bacteria strains from kefir grain (L. plantarum, L. fermentum, L. rhamnosus and L. acidophilus) with regard to fermented cow’s milk with the same bacteria strains. The assessment of antioxidant potential was made by ABTS, DPPH, TPC and FRAP methods. The work also assessed metabolic activity of tested lactic acid bacteria using measurement of electrical impedance changes in the growing medium. The highest values describing the antioxidant potential were found for fermented milk by L. acidophilus. It was also found that the time of cooling storage causes significantly increasing the antioxidant potential of most analyzed samples. Metabolic activity of tested lactic acid bacteria was the highest for cow’s milk. The course of curves for goat’s milk and whey from goat’s milk was similar, which confirms the differences between cow and goat milk.