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  • Investigation of the Azorean Camellia sinensis Processing Conditions to Maximize the Theaflavin 3,3'-di-O-Gallate Content as a Potential Antiviral Compound
    Publication . Paiva, Lisete; Lima, Elisabete; Motta, Madalena; Marcone, Massimo; Baptista, José
    ABSTRACT: The molecular constituents of Camellia sinensis, in particular epigallocatechin‐3‐O‐gallate (EGCG) and, more remarkably, the galloylated theaflavins, mainly theaflavin‐3,3′‐di‐O‐gallate (TF‐3,3′‐DG), have been reported to inhibit SARS‐CoV‐2 3‐chymotrypsin‐like protease (3CLpro), an enzyme required for the cleavage of its polyproteins, to produce vital individual functional proteins for viral cell replication. Our results for total catechin content revealed the values of 174.72, 200.90, and 211.75 mg/g dry weight (DW) in spring, and the values of 183.59, 191.36, and 215.09 mg/g DW in summer, for tea plantation zones 1, 2, and 3, respectively. For the TF‐3,3′‐DG content, the values of 2.68, 1.13, and 3.72 mg/g DW were observed in spring, and the values of 3.78, 2.06, and 8.91 mg/g DW in summer for zones 1, 2, and 3, respectively. In the same zone, different contents of TF‐3,3′‐DG were observed across plucking months of April, June, and August, with values of 1.13, 2.77, and 4.18 mg/g DW, respectively, showing higher values in summer. Different values of TF‐3,3′‐DG contents were also observed in the same tea plantation zone but from different plant parts, revealing higher values in the bud and the first and second leaves (3.62 mg/g DW) and lower values in the third and fourth leaves (1.14 mg/g DW). The TF‐3,3′‐DG content increased from 3.31 to 4.98 mg/g DW with increased fermentation time from 1 to 3 h, respectively, and increased for lower temperature and longer fermentation time. The aim of this study was to investigate the processing conditions that lead to maximum TF‐3,3′‐DG content and, given its potential impact as an inhibitor of the 3CLpro enzyme, to create a novel antiviral Azorean black tea.
  • Angiotensin I-converting enzyme (ACE) inhibition and biological activities of green and black tea samples from Azorean Camellia sinensis
    Publication . Paiva, Lisete; Lima, Elisabete; Marcone, Massimo; Baptista, José
    ABSTRACT: The inhibition of ACE can be targeted in order to control hypertension and much attention has recently been paid towards the search for natural products as alternatives to synthetic drugs due to their adverse side effects associated with them. Camellia sinensis tea has received considerable attention due to the beneficial effects on health, particularly as a result of its antioxidant properties. The objective of this study was to investigate the ACE inhibition of different types of Azorean C. sinensis tea samples and consequently its ability to reduce hypertension, relating it to antioxidant activity, catechin profiles, total phenolic content (TPC) and total flavonoid content (TFC) in different seasons. The results clearly highlighted differences in ACE-inhibition, FRSA, FRAP, FIC activity, TPC and epicatechin content among samples and the best results were observed in green tea collected in the summer. For TFC, higher values were observed in black tea harvested during the summer. In conclusion, the differences are related to the effect of collecting seasons, with the higher values being found in the summer with respect to the spring season.
  • The Surplus Value of HS-SPME/GC on the Rapid Quality Assessment of Dairy Products, Particularly Cheese, by The Volatile Components Profile
    Publication . Paiva, Lisete; Baptista, José
    ABSTRACT: Food aroma is a sensory property produced by the interaction between chemical compounds and sensory receptors and, particularly, cheese aroma consumer perception is one of the foremost criteria for its preference and acceptance. Head-space solid phase microextraction gas chromatography (HS-SPME/GC) is commonly used for qualitative and quantitative analysis of volatile compounds in various food products, in which analytes are adsorbed directly on the stationary phase coated on the outer surface of fuse-silica, eliminates the needs for solvent-extraction and/or sophisticated apparatus, requires much less sample preparation and manipulation time per sample. Bearing all this in mind, the aim of the present study was to determine and to compare cheese aroma profiles, particularly from Azorean Region, influenced by climate, soil composition, seasons, different management, and feed practices, genetic modified cows, and probably different cheese-making technologies using HS-SPME/GC methodology. Significant differences were observed in levels of individual head-space volatiles in different cheese aroma samples.
  • Significative Inactivation of SARS-CoV-2 3CL- Protease by Camellia sinensis Galloylated theaflavins: Processing conditions to maximize TF-3,3 -DG content
    Publication . Paiva, Lisete; Rato, Catarina; Baptista, José
    ABSTRACT: Since the last decade of the 19th century, the Camellia sinensis tea plant is commercially produced in one unique place in Europe, the volcanic São Miguel Island of the Azores Archipelago (Portugal) [1,2]. The molecular constituents of C. sinensis, in particular the galloylated theaflavins, mainly theaflavin-3,3’-di-O-gallate (TF-3,3’-DG), have been reported to inhibit SARS-CoV-2 3-chymotrypsin-like protease (3CLpro), a crucial enzyme required for the cleavage of its polyproteins (1a and 1ab) to produce vital individual functional proteins for viral cell replication [3]. According to Ohgitani [4] the virus treated with galloylated theaflavins, particularly TF-3,3’-DG, at 100 µM showed less than 1/10.000 infectivity compared to untreated virus. The TF-3,3’-DG content increased 50.91% with increased fermentation time from 1 to 3 hrs at room temperature (RT) and increased 41.26% at 35 °C of fermentation temperature. Furthermore, TF-3,3’-DG increased 29.40% with increasing temperature from RT to 70 °C in short extraction time (1:30 hrs) and oppositely decreased 18.44% with increasing temperature from RT to 70 °C in long extraction time (16:00 hrs). Taking all of the in vitro reported studies by several research teams and the in vivo results comparing the COVID-19 infections (mortality per million of population) in high tea consumption (4.28%) as compared with low tea consumption countries [5], the aim of this study was to investigate the steps of tea manufacturing conditions which lead to maximum TF-3,3’-DG content and, given its potential impact as an inhibitor of the 3CLpro enzyme, to create a novel antiviral Azorean black tea.
  • Determination of Melatonin in Azorean Bovine Milk by RP-HPLC as a Supplement for Sleepless Senior Population
    Publication . Paiva, Lisete; Baptista, José
    ABSTRACT: Melatonin (N-acetil-5-metoxitriptamine) is an indoleamine that is synthesized from the essential amino acid tryptophan via 5-hydroxytryptophan, serotonin and N-acetylserotonin in the vertebrate’s pineal gland, particularly during the nocturnal period (light suppress its biosynthesis) [1,2]. This neurohormone decreases with advancing age, paralleled by a deterioration of normal sleeping pattern and changes in circadian rhythmicity. It is frequently used as a sleep prescribed drug to reduce the symptoms associated to jetleg or shift work [3]. Furthermore, melatonin mediates many neuro-physiological, neuro-endocrinological and behavioral processes, and also participate in several other cellular functions, such as: cancers, Alzheimer`s disease, and depressive syndrome [4]. The objective of this study was the determination of melatonin in Azorean bovine milk (in the range of ppt), in order to make a good use of milk’s melatonin to supplement senior people that, generally, presents low level of this neurohormone, fact that increases with the progression of the ageing process. The results shows that Azorean milk melatonin level change according to the season of the year and also according to the nocturnal or diurnal milked periods, showing an average of 40.2 and 78.9 pg/ mL for diurnal and nocturnal periods, during winter period, respectively, and the values of 13.20 and 28.7 pg/mL for diurnal and nocturnal during summertime, respectively. The results also show that the heating treatment affect the melatonin content in the milk, revealing a decreasing level from the raw (46 pg/mL) to the pasteurized (31 pg/mL) and ultra-pasteurized (decreasing from 27 pg/mL at 120°C to 6.6 pg/mL at 150°C).
  • The Impact of Different Withering Process Conditions on the Bioactivity and Quality of Black Tea from Azorean Camellia sinensis
    Publication . Paiva, Lisete; Dias, Ana; Marcone, Massimo; Baptista, José
    ABSTRACT: The objective of this study was to investigate the variability of natural bioactive com pounds, such as catechin, theaflavin, total phenolic content (TPC), and total flavonoid content (TFC), of Azorean black tea (Camellia sinensis L., O. Kuntze) as well as its antioxidant activities according to different withering times. The TPC, TFC, free radical scavenging activity (FRSA), ferric reducing antioxidant power (FRAP), and ferrous-ion-chelating (FIC) activities were determined by colorimetric methods, and catechin and theaflavin contents were analyzed by high-pressure liquid chromatogra phy (HPLC). The FRSA shows similar results for the withering range of 6 to 16 h (hours). For FRAP, the best results were observed at 16 h, and for FIC, the highest value was at 20 h. The TPC and TFC showed the highest value at 9 h and the lowest at 20 h. For the total theaflavins, the highest results were obtained after 12 h of withering, and the lowest values were obtained at 16 and 20 h. According to the different withering times, the highest value of total catechin levels was at 12 h, while the lowest value was observed at 20 h. Regarding caffeine content, all samples presented similar results, with the exception of the 12 h time point. In conclusion, the best withering times were observed in the range of 9 to 16 h, showing decreased values at 20 h, with the exception of FIC.
  • A Natureza “pinta” os frutos do verão para os proteger da radiação solar ultravioleta
    Publication . Baptista, José; Paiva, Lisete
    Sabias que, do mesmo modo que usamos os cremes solares para protegermos a nossa pele dos efeitos negativos da radiação ultravioleta (UV), a NATUREZA usa compostos químicos coloridos para proteger os frutos do verão dos mesmos efeitos negativos criados pela radiação solar?