# Physicochemical and Sensory Analysis of Apple Cream Fillings for Use in the Pastry Industry
## 3 Results & Discussion
They are slightly acidic, which is typical for apple-based products due to the presence of organic acids like malic acid added not only as dried apple cubes (48 and 38% _w/w_ apple cubes for AP1 and AP2, respectively) but also as additive (0.26 and 0.32% _w/w_ for AP1 and AP2, respectively) [19]. The higher pH in PD is due to the presence of more neutral powdered ingredients like potato starch (28.00% in PD compared to 16.19 and 17.50% _w/w_ for AP1 and AP2, respectively) and dextrose (6.00% in PD compared to 3.45 and 3.00% in AP1 and AP2, respectively). The lack of acidic components from the  
Figure 1: **(a)** Moisture content and **(b)** Percentage of ash content (dash line) and volatile content (black line) of apple cream fillings (AP1, AP2, PD) and of raw materials (PDWW, DR-AP), where a,b,c the statistical letters provided to show the differences between the treatments. apple cubes and the presence of malic acid only as additive (0.5% _w/w_) results in a less acidic product. The lower pH of the dried apple cubes (DR.AP.) reflects their natural acidity, which is consistent with the high malic acid content in apples [4]. The dextrose pH ranges from 3.5 to 5.5 in 20% _w/w_. aqueous solution for dextrose monohydrated and near 5.9 (in 10% _w/w_. aqueous solution) for anhydrous dextrose [22]. The pH of xanthan gum is equal to 6.33 [24]. The pH value of sugar is near 6.0 to 7.0, while the pH values of dried apple chips range from 3.85 to 4.02 [31]. Titratable acidity (Figure 2b) deals with the measurement of the total acid concentration contained within a food and is a better predictor of acid's impact on flavor than pH. pH refers to the concentration of free hydrogen ions, while titratable acidity measures the total amount of acids, both free and bound, in a solution. Consequently, pH indicates the strength of acidity, while titratable acidity indicates the quantity of acids. The higher titratable acidity in AP1 and AP2 (0.157-0.18%) with no significant differences between them compared to P.D. is due to the presence of organic acids like malic acid [6]. Malic acid is used in apple cream fillings to enhance tartness and balance the sweetness of dextrose. It also acts as a pH regulator, ensuring the product remains within a safe acidity range to prevent spoilage. Its physicochemical properties, useful to the food industry, consist of its calcium chelating, buffer texturizer and antioxidant alleged properties [11]. It is a popular ingredient in fruit-based products due to its ability to mimic the natural acidity of fresh fruit. Its use has grown in recent years, particularly in clean-label and natural food formulations [19]. The existence of neutral powdered ingredients led to extremely low titratable acidity in P.D. (0.00174%). As is mentioned in literature [31], the titratable acidity of dried apple chips ranges from 0.71 to 0.95% according to apple varieties. According to [PERSON] and [PERSON], 2010 [32] the typical malic acid content in apple fruit is between 0.27 and 1.02%. In terms of acidity, this study's samples have significantly lower titratable acidity (less than 0.18%) compared to [PERSON] et al. study [4] (2.98-5.3%), suggesting a less pronounced sourness due to the minimal presence of fresh acidic compounds like organic acids. However, the pH of this study's samples (4.1-5.3) is slightly higher than theirs (3.89), reflecting a less acidic profile overall. The present paper samples reveal substantial differences compared to the results of [PERSON] et al., 2022 [6], who also used fresh ingredients. For pH, this study's samples (4.1-5.3) are, on average, 17.47% higher than theirs (3.3-4.6), reflecting a less acidic product. Regarding titratable acidity, the present samples with less  
Figure 2: Physicochemical characteristics of apple cream fillings (AP1, AP2, PD) and raw materials (DR.AP), i.e., (a) pH values, (b) fiber measurements (%), water activity and titratable acidity (%), where a,b,c the statistical letters provided to show the differences between the treatments.