Bioactive compound retention and shelf life extension of strawberry juice by selected nonthermal processing technologies
Başlık:
Bioactive compound retention and shelf life extension of strawberry juice by selected nonthermal processing technologies
Yazar:
Yıldız, Semanur, author.
Yazar Ek Girişi:
Fiziksel Tanımlama:
xx, 261 leaves: illustrarions, charts;+ 1 computer laser optical disc
Özet:
Shelf life extension of fruit juices while maintaining quality and functional properties is of great interest. Nonthermal food processing technologies have been emerged as innovative preservation methods alternative to thermal pasteurization of fruit juices. The objectives of this Ph.D. thesis were to (i) ensure microbial safety of strawberry juice (SJ) by thermal and nonthermal technologies, i.e. high pressure processing (HPP), ultrasound (US), pulsed electric field (PEF) and UV-C irradiation; (ii) evaluate physicochemical and phytochemical properties of SJ after processing and during storage; (iii) extend microbial shelf life of SJ without unduly affecting quality. HPP (300 MPa, 1 min), US (120 m, 5.15 J/mL, 55 C, 3 min), PEF (35 kV/cm, 27 s, 155 Hz), and thermal pasteurization (71.7 C, 15 s) conditions were determined based on equivalent inactivation of E.coli (ATCC 11775) in SJ studied at Washington State University. UV-C irradiation (1.01 J/mL, 53.9 C, 6 cycles, 5.8 min) and thermal pasteurization (72 C, 101 s) conditions were determined considering inactivation of E. coli K-12 (ATCC 25253) in SJ studied at IZTECH. Consequently, microbial shelf life of SJ treated by HPP, thermosonication, UVC+mild heating, thermal pasteurization was extended up to 42 days while PEF prolonged up to 35 days at refrigerated storage. Multivariate data analysis revealed that HPP and PEF enhanced phytochemical characteristics of SJ compared to thermosonication and thermal pasteurization. Although UV-C irradiation did not alter physcicochemical properties, total phenolic content, and antioxidant activities of SJ, total anthocyanin content was significantly decreased by UV-C light compared to untreated juice.
Yazar Ek Girişi:
Tüzel Kişi Ek Girişi:
Tek Biçim Eser Adı:
Thesis (Doctoral)--İzmir Institute of Technology: Food Engineering.
İzmir Institute of Technology: Food Engineering--Thesis (Doctoral).
Elektronik Erişim:
Access to Electronic Versiyon.