Impact of Thermal Blanching and Thermosonication Treatments on Watercress (Nasturtium officinale) Quality: Thermosonication Process Optimisation and Microstructure Evaluation

• Type: Article in International Scientific Journal
• Date: 2011

Authors

Cruz, RMS (Author) Other; Vieira, MC (Author) Other; Fonseca, SC (Author) FCUP; Silva, CLM (Author) Other

Journal

Title: Food and Bioprocess Technology

Vol. 4

Pages: 1197-1204

ISSN: 1935-5130

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 27 Citations

Scopus - 32 Citations

Other information

Authenticus ID: P-002-MDC

DOI: 10.1007/s11947-009-0220-0

Abstract (EN): The objectives of the present work were to optimise watercress heat and thermosonication blanching conditions, in order to obtain a product with better quality for further freezing, and to evaluate the effects of thermosonication on the microstructure of watercress leaves. In a chart of optimal time-temperature conditions for a 90% peroxidase inactivation (imposed constraint), vitamin C (objective function) and a-value (improvement toward green) were mathematically predicted for both heat and thermosonication blanching treatments. Two optimal thermosonication combinations were selected: 92 A degrees C and 2 s, retaining 95% of vitamin C content and 5% a-value improvement, and a better condition in terms of practical feasibility, 86 A degrees C and 30 s, allowing a 75% vitamin C retention and 8% a-value improvement. The experimental values, for each thermosonication optimal time-temperature zone, were in good agreement with the models' predicted responses. In terms of microstructure, thermosonicated watercress at 86 and 92 A degrees C showed similar loss of turgor and release of chloroplasts. The proposed optimal thermosonication blanching conditions allow the improvement of the blanched watercress quality and consequently contribute for the development of a high-quality new frozen product. However, a suitable scale-up is mandatory for industrial implementation.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8