Yazar "Tiwari, Brijesh K." seçeneğine göre listele

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    Effect of ultraviolet light emitting diode treatments on microbial load, phenolic and volatile profile of black peppercorns
    (Elsevier, 2021) Hinds, Laura M.; Güçlü, Gamze; Kelebek, Haşim; Selli, Serkan; O'Donnell, Colm P.; Tiwari, Brijesh K.
    This study investigated the potential of ultraviolet light emitting diode (UV LED) technology as a decontamination tool in the food industry. Black peppercorns were subjected to UV LED treatment at selected wavelengths (280, 300 and 365 nm) and treatment durations (5, 10 and 20 min). Microbiological analysis of treated black peppercorns inoculated with B. subtilis was carried out along with quality analysis using phenolic and volatile profile analysis. The initial concentration of B. subtilis in black peppercorn samples (7.18 +/- 0.17 log10 cfu g(-1)) was significantly reduced to 6.20 +/- 0.44 log(10) cfu g(-1) after treatment at 280 nm for 20 min, Piperine and piperyline were determined as the predominant phenolic compounds by LC-DAD-ESI-MS-MS and piperine exhibited a similar pattern to total phenolics with the highest concentration observed after 5 min treatment. Volatile profile analysis indicated an increase of sesquiterpenes, while monoterpenes decreased in concentration after UV LED treatment. Multivariate analysis showed the effects of UV LED treatments on all volatile compounds investigated. This study demonstrates the potential of UV LED treatment for processing of black peppercorns.
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    Exploring pilot scale ultrasound-microwave assisted extraction of organic acids and phytochemicals from brown seaweed Alaria esculenta
    (Elsevier, 2025) Das, Rahel Suchintita; Tiwari, Brijesh K.; Selli, Serkan; Kelebek, Hasim; Garcia-Vaquero, Marco
    This study investigates ultrasound (US) and microwave (MW) technologies - both applied individually (ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE)) and simultaneously (ultrasound-microwave-assisted extraction (UMAE)) for extracting bioactive compounds from a brown seaweed Alaria esculenta. This research emphasizes sustainability by using wet biomass and water for extraction. Employing a range of power (336-1340 W (MW); 50-200 W (US)) and time (5-20 min) conditions, the study evaluates multiple phytochemicals as well as antioxidant activities in the obtained extracts. The highest total soluble carbohydrate contents (32.68 mg glucose equivalents (GE)/100 mg extract) were achieved by UAE (200 W, 20 min). UMAE (50 W (US), 1340 W (MW), 10 min) had the highest levels of total phenolic contents (2.07 mg gallic acid equivalents (GAE)/100 mg extract) and FRAP (38.36 mu M Trolox equivalents (TE)/mg extract). The highest protein content (15.62 +/- 1.69 bovine serum albumin equivalents (BSAE) mg/100 mg extract) was recorded by UMAE (100 W (US), 1340 W (MW), 20 min). MAE (1340 W, 20 min) achieved the highest levels of succinic (7.52 mg/g extract) and lactic acids (39.08 mg/g extract), while UMAE (670 W (MW), 100 W (US), 5 min) extracted the highest amounts of malic (3.02 mg/g extract) and alpha-ketoglutaric acids (2.41 mg/g extract). Lactic acid, followed by pyruvic acid was the major organic acid present in the extracts. Scanning electron microscopy images confirmed increased cell damage in the biomass by all the treatments, with higher levels of surface roughness and enlarged pores appreciated after UMAE. Hence, this work being among the first to demonstrate US and MW application, both individually and simultaneously, on Alaria esculenta, utilizing an integrated commercially available pilot-scale system and a green extraction solvent, sheds light on the extraction of valuable phytochemicals including underexplored organic acids which hold immense potential for diverse applications.
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    Impacts of novel blanching treatments combined with commercial drying methods on the physicochemical properties of Irish brown seaweed Alaria esculenta
    (Elsevier Ltd, 2022) Zhu, Xianglu; Healy, Laura E.; Sevindik, Onur; Sun, Da-Wen; Selli, Serkan; Kelebek, Haşim; Tiwari, Brijesh K.
    Alaria esculenta is one of the most abundant edible brown seaweeds in Irelandandisconsidered an excellent source of nutrients, sought after by the food, nutraceutical and pharmaceutical industries. Seaweed is typically blanched and dried prior to consumption to enhance the end-product quality attributes and shelf life. Three blanching techniques were examined in this work; conventional hot water blanching, novel ultrasound blanching and microwave blanching. The L* and b*colour metrics were affected significantly (P < 0.01) by the processing methods. There were 76 volatile compounds detected in blanched and dehydrated Alaria esculenta. Freeze-dried samples after treatment with microwave alone (at 1000 W) and microwave (800 W) combined with ultrasound (at 50% amplitude) had the highest retention rate of volatile compounds (up to 98.61%). Regarding mineral content, drying methods significantly affected (P < 0.05) the content of Ca, Co, Cu and Fe, while blanching treatments significantly affected (P < 0.05) the content of Na, Cu, Fe and Mn. © 2021 Elsevier Ltd