Effect of Blanching Time–Temperature on Potassium and Vitamin Retention/Loss in Kale and Spinach
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Date
2024-03
Authors
Mugo, Beatrice Muthoni
Kiio, Juliana
Journal Title
Journal ISSN
Volume Title
Publisher
WILEY
Abstract
Hyperkalemia is common among patients with end stage kidney disease. Management
involves diet modification. Hot water blanching is recommended to leach potassium in
vegetables which results in losses of water-soluble and heat labile vitamins. Evidence
on the effect of blanching in reducing potassium level of locally consumed vegetables
in Kenya is limited. This study sought to establish effect of hot water blanching timetemperature on level of potassium, vitamin B1, B3 and C in kales (Brassica oleracea
var. acephala) and spinach (Spinach oleracea) on potassium and vitamins B1, B3 and C
retention/loss. The study adopted a full factorial experimental design. Vitamins were
determined using high performance liquid chromatography. Potassium was quantified
using atomic absorption spectrophotometry. To compare nutrient content between
samples, independent t-test and Analysis of Variance were used at 95% confidence
level. Nutrient content of fresh kales and spinach were potassium (102 mg/100 g and
615 mg/100 g), vitamin B1 (124 μg/100 g and 51 μg/100 g), vitamin B3 (1165 μg/100 g
and 812 μg/100 g) and vitamin C (102 mg/100 g and 116 mg/100 g) respectively. In
kales, blanching for 20 min at 1000°C resulted to retention of 86.9%, 55.6%, 27.6%
and 12.9% of vitamin B1, B3, C and potassium respectively. In spinach, blanching for
20 min at 1000°C resulted in retention of 79.9%, 88.6%, 12.2% and 40.6% retention
of vitamin B1, B3, C and potassium respectively. Vitamin C and Potassium were the
most sensitive to heat and leaching. Time had a greater effect than temperature in
this study. This study recommends blanching of kale at 15.2 min at 800°C, spinach
at 17.7 min at 840°C. Further research on optimal blanching time-temperature for
potassium and vitamin retention/loss is recommended.
Description
Article
Keywords
blanching, end stage kidney disease, nutrient retention, potassium leaching
Citation
Mugo, B. M., Kiio, J., & Munyaka, A. (2024). Effect of blanching time–temperature on potassium and vitamin retention/loss in kale and spinach. Food Science & Nutrition.