Functionality of spray-dried strawberry powder: effects of whey protein isolate and maltodextrin

Figures & data

Figure 1. Effect of WPI addition on the surface tension of strawberry puree.

Figure 2. Recovery of strawberry powder in the presence or absence of MD or WPI alone.

Figure 3. Effect of MD and WPI addition on the recovery of strawberry powder (with strawberry solid ratios in the feed solution fixed at 60%).

Table 1. Moisture content (MC), water activity (a_w), bulk density (D_B), and particle size (D_[4,3]) of spray-dried strawberry powder.

S:MD:WPI ratio	MC (%)	aw	DB (g.mL^−1)	D^[Citation3,Citation4] (μm)
60:40:0	4.52 ± 0.06^c	0.208 ± 0.003^b	0.55 ± 0.01^a	8.87 ± 0.01^a
60:39.5:0.5	4.92 ± 0.11^a	0.218 ± 0.006^a	0.53 ± 0.01^ab	8.67 ± 0.01^ab
60:39:1	4.85 ± 0.24^a	0.214 ± 0.004^b	0.51 ± 0.01^b	8.62 ± 0.01^ab
60:35:5	4.73 ± 0.17^b	0.21 ± 0.01^b	0.48 ± 0.03^b	8.29 ± 0.01^b
60:30:10	4.63 ± 0.11^b	0.213 ± 0.001^b	0.45 ± 0.06^c	7.12 ± 0.01^c

S: strawberry; MD: maltodextrin; WPI: whey protein isolate.

Different letters in the same column indicate a significant difference (p＜0.05).

Table 2. Glass transition temperature of spray-dried strawberry powders.

Sample	MC (%)	Tgi	Tgm	Tge
S:MD:WPI = 60:40:0	4.52 ± 0.06^c	29.03 ± 0.71^c	32.60 ± 1.16^c	34.17 ± 1.74^c
S:MD:WPI = 60:39.5:0.5	4.92 ± 0.11^a	30.71 ± 0.93^b	34.17 ± 1.24^b	36.22 ± 1.65^b
S:MD:WPI = 60:39:1	4.85 ± 0.24^a	31.26 ± 0.65^a	36.91 ± 0.95^a	40.45 ± 1.78^a
S:MD:WPI = 60:35:5	4.73 ± 0.17^b	32.55 ± 0.53^a	37.15 ± 1.45^a	42.73 ± 1.93^a
S:MD:WPI = 60:30:10	4.63 ± 0.11^b	33.85 ± 0.52 ^a	38.39 ± 1.83^a	43.60 ± 1.45^a
MD	3.50 ± 0.30	137.22 ± 3.51	141.14 ± 3.54	149.34 ± 3.15
WPI	3.30 ± 0.10	125.61 ± 1.82	128.62 ± 2.82	137.44 ± 2.12

Results are mean ± standard deviation (n = 3); Different letters in the same row indicate significant different (p < 0.05).

Figure 4. SEM micrographs of spray-dried strawberry powder produced with different formulations of drying aids: (a) 40% MD (b) 39.5% MD + 0.5% WPI (c) 39% MD + 1% WPI (d) 35% MD + 5% WPI (e) 30% MD + 10% WPI (at × 5000 magnification).

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