Development and validation of a predictive model for the influences of selected product and process variables on ascorbic acid degradation in simulated fruit juice

Estimation of ascorbic acid reduction in heated simulated fruit juice systems using predictive model equations

“…Some of the results obtained in this work are in agreement with, and hence confirmed those earlier reported by Gabriel et al (2015). In this earlier work, the influences of intrinsic fruit juice properties, titratable acidity (TA, % citric acid) and soluble solids (SS, Brix, % sucrose), and the same set of extrinsic process variables, heating temperature and exposure time (similarly based on the D-values of E. coli O157:H7 established by Gabriel (2012)) on ascorbic acid degradation was quantified using response surface predictive modeling.…”

“…Exposure time increase at any fixed heating temperature steadily increased %AA r values. These observations are in agreement with those reported in Igwemmar, Kolawole, and Imran (2013), Njoku, Ayuk, andOkoye (2011), andGabriel et al (2015). Furthermore, a steady linear decrease in the retention of vitamin was observed with decreasing initial concentration.…”

“…The experimental design consisted of 16 factorial combinations of high and low settings, 8 axial combinations of very low/very high and intermediate settings, and 12-time replicated center point combinations where all factors were set to intermediate values. In the CCRD, the ranges for the variable settings of pH and initial AA concentration were based on the reported physicochemical characteristics of fresh and processed citrus juice products in the study of Gabriel et al (2015). Furthermore, the temperature and time ranges were based on the previously established decimal reduction times (D-values) of E. coli O157:H7 in simulated fruit juices at varying heating temperatures (Gabriel, 2012).…”

“…Points plotted on the LOE indicate perfect prediction values (A f ¼ B f ¼ 1.00) (Ross, McMeeking, & Baranyi, 2014). Points plotted above the LOE represent overestimation of the measured responses (A f ¼ B f > 1.00) while points plotted below the LOE represent underestimation of the measured responses (A f >1.00, B f < 1.00) (Gabriel et al, 2015). Furthermore, a point that lies farther from the LOE indicates less agreement between the predicted and actual values.…”

“…Gabriel et al (2015) previously compared this AA quantification technique with other analytical techniques including the titrimetric assay using 2,6-dichloroindophenol (Nielsen, 2010), and a spectrophotometric assay using 2,4-dinitrophenylhydrazine (Kapur et al, 2012). The spectrophotometric method with NaOx was identified most appropriate based on how accurately it determined known amounts of AA in known standard solutions (Gabriel et al, 2015).…”