Extract of Ellagitannins starting with Strawberries (Fragaria sp.) and Blackberries (Rubus sp.)

Comparative analysis of β-glucosidase activity in non-conventional yeasts

The objective of this study was to evaluate the β-glucosidase activity in the non-conventional yeasts under cellulose, glucose and sucrose substrates. The participation of the enzyme β-glucosidase and its contribution to the enzymatic degradation of tannins is known. Within the classification of tannins are ellagitannins, molecules of gallic acid and ellagic acid, which are considered as nutraceutical compounds due to the properties that they present and that they can be used in the design of food and new drugs, synthesis of materials with antimicrobial capacity. The extracellular β-glucosidase activity was mainly presented in the Candida and Pichia strains, being the glucose and sucrose media the most capable for inducing the activity that showed maximum values with P. pastoris in glucose (0.1682±0.00 µmol/min mg protein), and C. utilis in cellulose (0.1129±0.1349 µmol/min mg of protein), and sucrose (0.0657±0.0214 µmol/min mg protein). Additionally, I. terricola and P. kluyvery stood out in a qualitative cellulose degradation approach measured by Congo red method (9.60±0.04 mm and 9.20±0.05 mm respectively). These indicate that P. pastoris and C. utilis have potential as β-glucosidase producers, especially when growing under complex carbon sources for biomass conversion, new biofuels production and polyphenol degradation with more manageable bioreactor process.

Reconnoitring the antioxidant and antibacterial potential of different fruits after tannin acyl hydrolase mediated biotransformation

Condensed and hydrolyzable tannins are secondary metabolites present in almost every plant part. Tannase enzyme acts on hydrolyzable tannins to produce gallic acid and tannase-mediated end-products with immense therapeutic potential. Seven different fruits with significant presence of hydrolyzable tannin content were selected to check for phenol, tannin, and hydrolyzable tannin contents. Prunus domestica had the maximum phenol content, that is, 85.4 ± 0.207, followed by Syzygium cumini, Fragaria ananassa, Rubus fruticosus, and Psidium guajava. Plum showed the maximum number of hydrolyzable tannins. Fruit extracts were subjected to tannase hydrolysis and their antimicrobial and antioxidant activities were determined. There was a significant increase in the antioxidant abilities of the fruits with Punica granatum extract, displaying the highest decline of 132 units of IC50 followed by F. ananassa hydrolyzable extract, showing a decrease from 224.75 to 119.98 μg/mL. The extracts also depicted a significant increase in antibacterial activity after hydrolysis against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus with Rubus idaeus aqueous extract observed to be most effective against E. coli. The increase in antioxidant and antibacterial activity can be attributed to the production of tannase-mediated products formed after the biotransformation of hydrolyzable tannins present in the aqueous extracts.

Hydrolysable tannins, physicochemical properties, and antioxidant property of wild-harvested Terminalia ferdinandiana (exell) fruit at different maturity stages

Terminalia ferdinandiana Exell., also known as Kakadu plum, is a wild-harvested native Australian fruit with limited information on how maturity is affecting the phytonutritional properties and bioactivities of the fruit. Thus, this study investigated changes in hydrolysable tannins, phenolic acids, sugar profile, standard physicochemical parameters, and antioxidant-scavenging capacity of wild-harvested Kakadu plum fruits at four different maturity stages, from immature to fully mature. Fruits harvested <25, 25-50, 50-75, and 75-100% degree of fullness were classified as highly immature (stage 1), immature (stage 2), semi-mature (stage 3), and fully mature (stage 4), respectively. Results showed that chebulagic acid, geraniin, chebulinic acid, castalagin, punicalagin, and gallic acid continuously decreased during fruit maturity, while elaeocarpusin, helioscopin B, corilagin, 3,4,6-tri-O-galloyl-S-glucose, and ellagic acid increased at the beginning of fruit growth (from stage 1 to 2), but decreased when the fruits reached their full maturity (stage 4). The levels of hydrolysable tannins and phenolic acids in fully mature fruits (stage 4) were significantly (p ≤ 0.05) lower than that in their immature counterparts (stages 1 and 2). Total phenolic content (TPC) and DPPH antioxidant radical-scavenging activity did not vary significantly between different maturity stages. Pearson's correlation coefficient test indicated that TPC and DPPH positively (p ≤ 0.05) correlate with most of the studied tannin compounds. Sugars (glucose, fructose, and sucrose), total soluble solid content, and titratable acidity increased during the fruit development. Furthermore, principal component analysis (PCA) revealed the difference between the immature and mature samples, based on their nutritional profile and bioactive compounds. The PCA results also suggested a considerable variability between the individual trees, highlighting the challenges of wild-harvest practice.

The Kinetics of Two-Step Ellagitannin Extraction from the By-products of Selected Processed Fruits of the family Rosaceae

The paper presents the kinetics of two-step ellagitannin (ET) extraction with an aqueous acetone solution from two technological types of pomace from selected berry fruits of the Rosaceae family. ETs were identified and quantified using HPLC–MS and HPLC–DAD. The results revealed the extraction kinetics of total ETs, their high and low molecular weight fractions (≤ 1569 Da and > 1569 Da), and individual ETs characteristic of the examined fruits. ET extraction proceeded at a faster rate in the first step, regardless of the tested pomace. For all pomace variants, the mean extraction half time t1/2 was 48 min in the first step and 70 min in the second step. The fruit species and the technological type of pomace were not found to exert a definite effect on the kinetics of ET extraction. Statistical analysis demonstrated that the molecular weight of ETs did not influence the kinetics of their extraction, either. It was shown that the technological type of pomace had a significant impact on the extraction rate of both low molecular weight (LMW) and high molecular weight (HMW) ETs in the first extraction step, with the mean t1/2 being 44 min for pomace from juice production and 63 min for pomace from puree production.