Testing for sensory threshold in drinking water with added calcium: a first step towards developing a calcium fortified water

Abstract

Background: Food fortification is an effective strategy that has been recommended for improving population calcium inadequate intakes. Increasing calcium concentration of water has been proposed as a possible strategy to improve calcium intake. The objective of this study was to determine the sensory threshold of different calcium salts added to drinking water using survival analysis. Methods: We performed the triangle test methodology for samples of water with added calcium using three different calcium salts: calcium chloride, calcium gluconate and calcium lactate. For each salt, a panel of 54 consumers tested seven batches of three water samples. Data were adjusted for chance and sensory threshold was estimated using the survival methodology and a discrimination of 50%. Results: The threshold value estimation for calcium gluconate was 587 ± 131 mg/L of water, corresponding to 25% discrimination, for calcium lactate was 676 ± 186 mg/L, corresponding to 50% discrimination, and for calcium chloride was 291 ± 73 mg/L, corresponding to 50% discrimination. Conclusions: These results show that water with calcium added in different salts and up to a concentration of 500 mg of calcium/L of water is feasible. The calcium salt allowing the highest calcium concentration with the lowest perceived changes in taste was calcium gluconate. Future studies need to explore stability and acceptability over longer periods of time.

Calculation of the contribution of water to calcium intake in low‐ and middle‐income countries

“…Simulations in population groups of LMICs have shown that water with up to 500 mg of calcium per liter of water increases the percentage of people reaching adequate intake without exceeding the recommended upper limit for calcium intake 7 . In laboratory tests, we found that table water containing 20 mg of calcium per liter could reach up to 100 mg of calcium per liter by adding calcium chloride 31 . This water complied with WHO standards for tap water 31 .…”

“…7 In laboratory tests, we found that table water containing 20 mg of calcium per liter could reach up to 100 mg of calcium per liter by adding calcium chloride. 31 This water complied with WHO standards for tap water. 31 Higher levels could be reached using organic salts; however, when using organic salts, the final water could only be distributed in containers or bottles or prepared at the point of use by adding the calcium salts.…”

“…31 This water complied with WHO standards for tap water. 31 Higher levels could be reached using organic salts; however, when using organic salts, the final water could only be distributed in containers or bottles or prepared at the point of use by adding the calcium salts. Using a triangle test, a water consumer panel perceived no difference in organoleptic properties between table water containing 20 mg of calcium per liter and the same water with added calcium.…”

“…The threshold for calcium gluconate is 587 ± 131 mg of calcium per liter. 31 Further research will be necessary for this possible intervention, including investigating the technical feasibility of incorporating calcium salts, the economic impact of using public water sources, the organoleptic acceptability in different populations, and local regulatory aspects. Much of the added calcium to tap water could be wasted, as most domestic water is not used for human drinking.…”

“…The taste threshold for calcium chloride was 291 ± 73 mg of calcium per liter. The threshold for calcium gluconate is 587 ± 131 mg of calcium per liter 31 …”