Evaluation of in-line absorption photometry to predict consistency of concentrated tomato products

This study evaluated the correlation between optical density as measured by absorption photometry, water-insoluble solids (WIS) and consistency as measured by the Bostwick consistometer for a variety of concentrated tomato products. Linear regression analysis indicated a linear correlation (R-2 =0.97) between optical density and WIS content in diluted tomato paste,. a linear correlation (R-2 greater than or equal to0.92) between optical density and consistency in various commercial tomato products and a linear correlation (R-2 =0.93) between optical density and consistency during commercial production of tomato puree made from ripe tomatoes. The optical density appeared to be unaffected by product temperature and flow rate. Potential limitations of in-line absorption photometry to monitor and control tomato product consistency are briefly discussed. (C) 2002 Swiss Society of Food Science and Technology. Published by Elsevier Science Ltd. All rights reserved.