APS Journal April 2017

A pricot

79

Biplot of variables and individuals ratings PCA

4

flavor

Groups

overall.quality

'Brookcot'

'Debbie's Gold'

2

sweetness

'Sungold'

color

bitterness

'Westcot'

fruit.pieces off.flavor

apricot control

spread

texture

0

cherry control

MN202

Dim2 (15.1%)

MN203

−2

MN206

MN604

plum control

−4

−2

0

2

4

Dim1 (25.2%)

Fig. 4. Biplots from principal components analyses measured variables for the apricot jams and comparisons used in the (A) chemical analysis for mean soluble solids, pH, titratable acidity (g/L citric acid equivalent) L*a*b* color space or CIELAB (where L* indicateslightness; a* and b* are the chromaticity coordinates), hue angle (H ab * = arctan(b*/a*) and chrome (C ab * = sqt [a* 2 +b* 2 ]) and (B) sensory evaluation panels for fruit pieces, flavor, off-flavor, sweetness, color and overall quality (10-point scale); spreadability, texture and bitterness ratings on a 0 to 10 scale.

 Apricot jam color, as gauged by color lightness (L*), is one of the most important consumer selection criteria (Touati et al., 2014). L* was the lightest for ‘Brookcot’ jam (Table 1). The panelists in the sensory evaluation were also able to discern differ- ences among the apricot jams and their com- parisons for color (Table 2). Since apricot fruits range in colors of yellow to orange and red when ripe, chromaticity coordinates of blue-yellow (b*) indicate that ‘Debbie’s Gold’ was the yellowest apricot jam and sig- nificantly yellower than MN206, ‘Westcott’, the tart cherry and plum controls (Table 1). In contrast to ‘Brookcot’, apricot jams made

from MN604, MN206 and MN203 were sig- nificantly darker in color and were statisti- cally similar to the tart cherry control. Such darker-colored apricot jams, changing from yellower to more reddish tones may be due to the Maillard reaction whereby brown pig- mentation is formed or enzymatic browning occurs. The browning of jams has been ob- served in previous studies of apricot (Touati et al., 2014) and strawberry jams (Wicklund et al., 2005; Patras et al., 2011).  The panelists in the sensory evaluation were able to discern differences among the apricot jams and comparisons for spread- ability, texture, fruit pieces, flavor, off-flavor