Use of fermented olive paste for enrichment in bioactive compounds of typical Italian bakery products "tarallini"

Agri-food by-products produced during handling and processing of fruits and vegetables, represent a major waste disposal problem for industry, but they are also promising sources of bioactive compounds that can be recovered and used as valuable substances to develop new enriched food, such as pasta and bakery products. Tarallini are a typical Italian bakery products, that has currently become very popular worldwide as a savory snack or bread substitute. These products can be considered an optimal, cheap and easy-to-use carrier of phytochemicals. Olive fruit is an excellent natural source of unsaturated fatty acids, as well as other nutritionally important health- promoting bioactive compounds [1]. The modern two-phase technology of the Leopard series for olive oil industrial extraction developed by the Pieralisi Group (Pieralisi Maip S.p.A., Jesi, AN, Italy) generates large quantities of a novel by-product (olive paste - OP) made up of the partially defatted wet drupe pulp without any traces of the kernel. OP can be incorporated into wheat based products [2]. In this work the biotechnological aptitude of selected microorganisms, yeast and Lactic Acid Bacteria from different sources, were tested to transform OP in a new fermented product. Furthermore, some bioactive compounds, such as polyphenols, triterpenic acids, phytosterols, squalene, tocopherols and carotenoids, of fermented OP obtained from black olives belonging to Leccino and Cellina di Nardò cultivars, were characterized. Finally, new types of tarallini were produced by adding 10% of fermented and non-fermented OP to dough. The levels of bioactive compounds were compared with conventional control tarallini produced with the same semolina but without supplementations. The polyphenols content of olive paste, found in the olive paste Leccino (OPL) was 7.2 mg/g fresh (FW) while for olive paste Cellina di Nardò (OPC) the concentration was 18.1 mg/g FW. The fermentation of OP produces a decrease of phenolic concentration 20% for OPL and 16% for OPC. Among the oleuropein derivatives, 3,4- DHPEA-EDA, showed the higher reductions corresponding to the increase in their hydrolysis products (hydroxytyrosol), due to the enzymatic activity of the strains used for the fermentation of the OP [3]. Total triterpenic acid content was about 1.5 and 1.7 mg/g fresh weight in OPL and OPC respectively. These values did not differ significantly compared with the respective fermented OP. The total phytosterols and squalene content ranged between 1.7 mg/g FW (OPC) and 1.9 mg/g FW (OPL) and between 29.10 ?g/g FW (OPL) and 38.95 ?g/g FW (OPC), respectively. After fermentation, total phytosterols content was reduced from 53% to 49% whereas squalene level was reduced from 47% to 23% compared with not fermented OP. The content of tocochromanol and carotenoid did not differ significantly after fermentation process, their content ranged from 22.64 ?g/g FW (fermented OPL) to 24.94 ?g/g FW (not fermented OPL) for tocochromanols and from 3.26 ?g/g FW (fermented OPL) to 3.78 ?g/g FW (fermented OPC) for carotenoids. Furthermore, tarallini enriched with OP showed significantly higher levels of bioactive compounds than conventional tarallini. Nutrition facts labels describing nutrition information of tarallini supplemented with fermented and non- fermented OP have been produced. OP, due to its richness in bioactive compounds, may be exploited to enhance nutritional and health promoting properties of tarallini or other backery products Keywords: carotenoids; functional foods; industrial by-products; polyphenols; tocochromanols; triterpenic acids Acknowledgments This work was supported by Regione Puglia (research project PASSATADOLIVA). Acknowledgments are also due to Federazione Coldiretti Lecce, Coopolio Lecce, Olearia Murrone, Gepra srl, and Panificio Donato Caroppo for their valuable collaboration. References [1] Durante et al., 2017. J Sci Food Agric, 98(1), 96-103 [2] Padalino et al., 2018. Antioxidants, 7(4), 59 [3] Servili et al., 2006 J. Agric. Food. Chem., 54 (11), 3869-3875

Agri-food by-products produced during handling and processing of fruits and vegetables, represent a major waste disposal problem for industry, but they are also promising sources of bioactive compounds that can be recovered and used as valuable substances to develop new enriched food, such as pasta and bakery products. Tarallini are a typical Italian bakery products, that has currently become very popular worldwide as a savory snack or bread substitute. These products can be considered an optimal, cheap and easy-to-use carrier of phytochemicals. Olive fruit is an excellent natural source of unsaturated fatty acids, as well as other nutritionally important health- promoting bioactive compounds [1]. The modern two-phase technology of the Leopard series for olive oil industrial extraction developed by the Pieralisi Group (Pieralisi Maip S.p.A., Jesi, AN, Italy) generates large quantities of a novel by-product (olive paste - OP) made up of the partially defatted wet drupe pulp without any traces of the kernel. OP can be incorporated into wheat based products [2]. In this work the biotechnological aptitude of selected microorganisms, yeast and Lactic Acid Bacteria from different sources, were tested to transform OP in a new fermented product. Furthermore, some bioactive compounds, such as polyphenols, triterpenic acids, phytosterols, squalene, tocopherols and carotenoids, of fermented OP obtained from black olives belonging to Leccino and Cellina di Nardò cultivars, were characterized. Finally, new types of tarallini were produced by adding 10% of fermented and non-fermented OP to dough. The levels of bioactive compounds were compared with conventional control tarallini produced with the same semolina but without supplementations. The polyphenols content of olive paste, found in the olive paste Leccino (OPL) was 7.2 mg/g fresh (FW) while for olive paste Cellina di Nardò (OPC) the concentration was 18.1 mg/g FW. The fermentation of OP produces a decrease of phenolic concentration 20% for OPL and 16% for OPC. Among the oleuropein derivatives, 3,4- DHPEA-EDA, showed the higher reductions corresponding to the increase in their hydrolysis products (hydroxytyrosol), due to the enzymatic activity of the strains used for the fermentation of the OP [3]. Total triterpenic acid content was about 1.5 and 1.7 mg/g fresh weight in OPL and OPC respectively. These values did not differ significantly compared with the respective fermented OP. The total phytosterols and squalene content ranged between 1.7 mg/g FW (OPC) and 1.9 mg/g FW (OPL) and between 29.10 ?g/g FW (OPL) and 38.95 ?g/g FW (OPC), respectively. After fermentation, total phytosterols content was reduced from 53% to 49% whereas squalene level was reduced from 47% to 23% compared with not fermented OP. The content of tocochromanol and carotenoid did not differ significantly after fermentation process, their content ranged from 22.64 ?g/g FW (fermented OPL) to 24.94 ?g/g FW (not fermented OPL) for tocochromanols and from 3.26 ?g/g FW (fermented OPL) to 3.78 ?g/g FW (fermented OPC) for carotenoids. Furthermore, tarallini enriched with OP showed significantly higher levels of bioactive compounds than conventional tarallini. Nutrition facts labels describing nutrition information of tarallini supplemented with fermented and non- fermented OP have been produced. OP, due to its richness in bioactive compounds, may be exploited to enhance nutritional and health promoting properties of tarallini or other backery products Keywords: carotenoids; functional foods; industrial by-products; polyphenols; tocochromanols; triterpenic acids Acknowledgments This work was supported by Regione Puglia (research project PASSATADOLIVA). Acknowledgments are also due to Federazione Coldiretti Lecce, Coopolio Lecce, Olearia Murrone, Gepra srl, and Panificio Donato Caroppo for their valuable collaboration.