Effect of roselle extracts on the selected quality characteristics of ice cream

Figures & data

Table 1. Descriptors used for the sensory profiling of roselle-flavored ice creams.*

Sensory Attributes		Definitions	Standards	Scale
Appearance	Cream white	Cream white colour intensity.	Commercial vanilla ice cream (Nestlé South Africa Pty Ltd.)	0 = cream white 10 = strong cream white
	Grey	Grey color typical of ash.		0 = not grey 10 = intense grey
Taste	Sweetness	Evaluation of the sweet intensity. The product lacks bland or flat taste.	2% sucrose solution	0 = not sweet 10 = very sweet
Flavour	Vanilla flavour	Evaluation of vanilla intensity released during consumption.	Commercial ice cream (Nestlé South Africa Pty Ltd.)	0 = not perceived 10 = strongly perceived
	Milky	A flavor similar to that of fresh milk.	Commercial full cream fresh milk	0 = not intense 10 = very intense
Texture	Hard in scoop	Represent the resistance against scooping a small proportion of ice cream.	Commercial ice cream stored and assessed at – 28°C (Nestlé South Africa Pty Ltd.	0 = not 10 = very hard
	Coarse in scoop	The sample contains a significant number of detectable ice crystals which are perceived during scooping.	Commercial ice cream stored and assessed at – 28°C (Nestlé South Africa Pty Ltd.)	0 = not coarse 10 = very coarse
Mouthfeel	Icy mouthfeel	It refers to the freezing effect of the product which may be accompanied by tongue numbing.	An ice cream mix diluted by 50% milk prior to freezing	0 = not icy 10 = very icy
	Hard mouthfeel	The samples is characterised by a very stiff structure which is gradually diminished as the product melts.	Commercial ice cream stored and assessed at – 28°C (Nestlé South Africa Pty Ltd.)	0 = not hard 10 = very hard
	Coarse mouthfeel	The defect is evident during biting on the ice cream sample.	Commercial ice cream stored and assessed at – 28°C (Nestlé South Africa Pty Ltd.)	0 = not coarse 10 = very coarse
	Gummy	Food is pulled apart by downward movement of the tongue and the resulting threads are sensed as sticky by tongue, palate and throat, making swallowing difficult.	Addition of 0.3 g/100 g extra stabiliser to ice cream mix	0 = not
	Creamy	The sample is orally perceived as having a smooth texture, without any defects, melts uniformly to a thick and homogenous fluid.	A commercial vanilla ice cream (Nestlé South Africa Pty Ltd.)	0 = not creamy 10 = very creamy
	Watery	The sample melts unusually quickly to an uncharacteristically thin, watery fluid.	An ice cream without added hydrocolloids	0 = not watery 10 = very watery

*Adapted from Soukoulis and Tzia (2010)³⁰

Table 2. Color parameters of roselle-flavored ice cream

Sample	L*	a*	b*	WI	Hue (°)
Control	80.30^e ± 0.44	1.43^c ± 0.23	7.13^d ± 0.06	79.00^e ± 0.44	87.60^e ± 0.78
IC5	72.00^d ± 0.40	0.03^a ± 0.06	3.10^c ± 0.00	71.80^d ± 0.40	29.97^a ± 51.90
IC10	68.27^c ± 0.23	0.43^b ± 0.12	1.33^b ± 0.32	68.27^c ± 0.23	82.23^d ± 5.25
IC15	64.20^a ± 0.46	0.57^b ± 0.06	0.80^ab ± 0.17	64.20^a ± 0.46	62.27^c ± 8.22
IC20	65.07^b ± 0.12	1.50^c ± 0.00	0.43^a ± 0.67	65.03^b ± 0.15	36.63^b ± 38.81

Mean ± standard deviation; values in the same column with the same superscript letter are not statistically significantly different from one another at 95% confidence interval. Control = 0% roselle extract; IC5 = 5% roselle extract; IC10 = 10% roselle extract; IC15 = 15% roselle extract; IC20 = 20% roselle extract. L* denotes lightness from black (0) to white (100), a* redness (+) to greenness (-), b* yellowness (+) to blueness (-). The whiteness index indicates how near the sample is to an ideal white (WI = 100); hue indicates the chromaticity (0°, red; 90°, yellow; 180°, green; 270°, blue).

Table 3. Some physical characteristics of roselle-flavored ice cream

Ice cream samples	Overrun (%)	Melting rate (g/min)	Viscosity (cP)
Control	14.0^a ± 1.1	0.7^a ± 0.0	246.0^b ± 5.6
IC5	17.6^b ± 1.2	1.3^b ± 0.0	242.3^ab ± 3.2
IC10	20.9^c ± 1.8	1.6^c ± 0.2	239.3^ab ± 3.2
IC15	23.5^c ± 2.3	2.1^d ± 0.2	238.7^a ± 1.4
IC20	33.5^d ± 0.3	2.3^e ± 0.0	238.3^a ± 3.2

Mean ± standard deviation; values in the same column with the same superscript letter are not statistically significantly different from one another at 95% confidence interval. Control = 0% roselle extract; IC5 = 5% roselle extract; IC10 = 10% roselle extract; IC15 = 15% roselle extract; IC20 = 20% roselle extract; cP = centipoise.

Table 4. Selected chemical properties of roselle-flavored ice cream

Ice cream samples	pH	°Brix	Total solids	Titratable acidity (%malic acid)
Control	6.75 ± 0.03^b	35.48 ± 0.01^e	35.95 ± 1.76^c	0.16 ± 0.03^ab
IC5	6.74 ± 0.03^b	31.18 ± 0.02^d	34.82 ± 0.94^bc	0.15 ± 0.01^a
IC10	6.68 ± 0.05^b	30.28 ± 0.49^c	31.61 ± 5.30^abc	0.15 ± 0.01^a
IC15	6.48 ± 0.04^a	28.19 ± 0.56^b	30.75 ± 1.16^ab	0.19 ± 0.02^bc
IC20	6.33 ± 0.21^a	25.59 ± 0.42^a	27.29 ± 0.80^a	0.22 ± 0.02^c

Mean ± standard deviation; values in the same column with the same superscript letter are not statistically significantly different from one another at 95% confidence interval. Control = 0.0% roselle extract; IC = ice cream; IC5 = 5% roselle extract; IC10 = 10% roselle extract; IC15 = 15% roselle extract; IC20 = 20% roselle extract.

Table 5. Sensory characteristics of roselle-flavored ice cream as described by trained panel

	Ice cream formulations
Sensory attributes	Control	IC5	IC10	IC15	IC20
Cream white	7.5^d ± 0.5	4.3^c ± 0.5	2.9^b ± 0.8	2.8^b ± 0.9	1.6^a ± 0.9
Grey	0.4^a ± 0.5	5.5^b ± 1.2	6.4^c ± 0.5	7.5^d ± 0.5	8.1^d ± 0.4
Milky	5.9^b ± 0.8	4.9^bc ± 1.0	5.1^bc ± 1.8	4.5^bc ± 1.4	3.9^a ± 1.1
Vanilla	4.0^d ± 1.9	2.4^a ± 1.1	1.8^a ± 1.2	1.5^a ± 1.3	1.5^a ± 1.4
Sweetness	7.5^c ± 0.8	7.1^bc ± 0.6	6.9^bc ± 0.8	5.9^a ± 0.8	6.5^ab ± 0.8
Hard scoop	4.3^a ± 1.0	4.8^ab ± 0.9	5.8^c ± 1.0	6.1^c ± 0.8	5.5^bc ± 0.8
Coarse scoop	3.0^a ± 0.8	4.3^b ± 0.7	5.4^c ± 1.1	5.3^bc ± 0.7	5.75^c ± 1.5
Icy mouthfeel	3.6^a ± 1.1	5.3^b ± 0.7	5.8^bc ± 0.7	6.1^bc ± 0.8	6.3^c ± 0.9
Hard mouthfeel	3.4^a ± 0.5	4.3^ab ± 0.7	4.8^b ± 0.7	5.3^b ± 1.0	5.0^b ± 1.4
Coarse mouthfeel	3.3^a ± 0.7	4.3^bc ± 0.9	4.3^b ± 1.4	5.1^bc ± 0.8	5.8^c ± 0.7
Gummy	4.8^a ± 1.8	4.3^a ± 2.1	4.8^a ± 1.3	5.0^a ± 1.1	3.8^a ± 1.5
Watery	3.1^a ± 0.8	4.6^b ± 1.2	5.3^bc ± 1.0	6.3^c ± 0.7	4.9^b ± 1.5
Creamy	7.3^b ± 1.3	6.5^b ± 0.9	5.4^a ± 0.9	4.8^a ± 1.0	4.4^a ± 0.7

Mean ± standard deviation; values in the same row with the same superscript letter are not statistically significantly different from each other at 95% confidence interval. Control = 0.0% roselle extract; IC = ice cream; IC5 = 5% roselle extract; IC10 = 10% roselle extract; IC15 = 15% roselle extract; IC20 = 20% roselle extract.

Figure 1. Parameter loadings and factor scores for principal component 1 (PC1) and principal component 2 (PC 2).Control = 0% roselle extract; IC5 = 5% roselle extract; IC 10 = 15% roselle extract;IC20 = 20% roselle extract1