Development and Optimization of a System for the Extraction, Filtration, and Concentration of Date Fruit Syrup to Produce High-Quality Dips

Color and pH of the syrups produced

Pressure (mbar)	pH	ΔE*
1000	5.4b ± 0.01	42.8d ± 0.1
−1.8	5.4b ± 0.01	43.3c ± 0.1
−2.8	5.4b ± 0.01	46.4b ± 0.04
−5.5	6.0a ± 0.06	47.5a ± 0.03

Chemical parameters of commercial and sun evaporated dips

Pressure	Sugar (g per kg)	Protein (%)	Ash (%)	Acidity (%)	Moisture (%)
Commercial	628.8c±0.64	2.8b±0.03	1.7b±0.03	0.49b±0.01	19.5a±0.01
1000	719.7b±1.15	3.0b±0.1	1.8ab±0.03	0.53b±0.02	13.8b±0.05
−1.8	727.8b±2.25	4.0a±2.14	2.1a±0.01	0.64a±0.01	13.5b±0.01
−2.8	759.1a±2.25	3.8a±0.07	2.0a±0.02	0.66a±0.01	14.0b±0.03
−5.5	761.0a±3.46	3.9a±0.01	2.2a±0.04	0.68a±0.06	13.6b±0.02

Phenolic content and color in commercial and sun evaporated dips

Pressure (mbar)	Phenolics (mg GAE per 100 g)	ΔE
Commercial	4.8c ± 0.02	80.0b ± 0.02
1000	5.2b ± 0.10	84.5a ± 0.01
−1.4	5.7a ± 0.03	85.2a ± 0.02
−2.8	5.8a ± 0.02	85.2a ± 0.02
−5.5	5.9a ± 0.04	85.6a ± 0.02

TSS, pH and the color of concentrated date syrups (dips)

Pressure (mbar)	Sun concentration			Rotary concentration			T-test	P-value
	TSS	pH	ΔE	TSS	pH	ΔE
1000	87.4a ±0.60	4.9a ±0.01	84.5a±0.02	88.3a±0.03	4.2a±0.01	81.5a±0.03	312.01	0.0001
−1.8	87.7a±0.02	4.9a±0.01	85.2a±0.05	87.8a±0.02	4.2a±0.02	82.7±0.04a	42.66	0.0001
−2.8	87.9a±0.03	4.9a±0.06	85.2a±0.05	88.3a±0.02	4.2a±0.01	82.4a±0.04	38.23	0.0001
−5.5	88.0a±0.03	5.0a±0.08	85.6a±0.02	87.8a±0.07	4.3a±0.03	82.0a±0.08	33.01	0.0001

Mineral content (ppm) in commercial and sun evaporated dips

Pressure	Cr	Fe	Cu	Zn	Mg	Ca	Na	K	Mn
Commercial	29.7a±0.02	32.6b±0.02	15.8b±0.06	6.4c±0.01	268.3a±0.40	159.4c±0.10	45.5b±0.20	1166.0a±0.41	16.5a±0.12
1000 mbar	30.0a±0.02	32.9b±0.06	18.9a±0.06	19.0b±0.04	267.0a±0.20	197.3b±0.20	56.1a±0.20	1168.6a±0.36	16.8a±0.30
−1.8 mbar	31.4a±0.08	45.6a±0.03	18.6a±0.20	19.8b±0.06	271.9a±0.40	261.6a±0.01	55.5a±0.20	1170.7a±0.90	17.2a±0.30
−2.8 mbar	32.0a±0.01	46.2a±0.06	19.1a±0.20	22.3b±0.06	270.6a±0.02	256.3a±0.02	58.3a±0.20	1171.0a±0.80	17.3a±0.20
−5.5 mbar	32.5a±0.01	45.5a±0.02	19.2a±0.20	24.6a±0.02	274.6a±0.10	262.7a±0.02	57.0a±0.30	1170.8a±0.90	17.9a±0.30

Extraction and filtration of date syrup using a ladder system of 1_0, 0_25, 0_112, and 0_011-mm pore sizes at different pressures

Pressure (mbar)	Initial volume (ml)	Filtrate volume (ml)	Syrup yield (%)	TSS (Brix)	Residue volume (ml)	Moisture of residue (%)
1000	4523	3271	72	14.9a ± 0.04	1252	83
−1.8	4487	3226	72	14.6a ± 0.06	1261	83
−2.8	4560	3324	73	14.7a ± 0.03	1236	83
−5.5	4439	3236	73	14.9a ± 0.10	1203	84