The research, published in Food Research International, suggests that certain salty and umami tasting extracts from saltwort, sea tangle, and mushroom plants could be combined and used as a low sodium salt substitute for foods.
“When the degree of saltiness between plant salt substitutes and sodium chloride is the same, plant salt substitutes contains 43 per cent less sodium than sodium chloride. Therefore, plant salt substitutes can be used in food to reduce an individual’s sodium intake with the retaining the salty taste of sodium chloride,” wrote lead researcher Prof. Gyu-Hee Lee, from the Department of Food Science & Biotechnology at Woosong University, Korea.
Sodium is an essential nutrient, but the physiological need of is only around 0.5 grams per day – with excessive sodium intake implicated in conditions such as high blood pressure (hypertension) and cardiovascular diseases.
Approximately one quarter of adults have hypertension, which is a major risk factor for coronary diseases, stroke, and premature death. However, the researchers noted that because sodium is ubiquitous in food products, reductions in intakes are not easily attainable.
Prof Lee states that 75 per cent of sodium intake is derived from processed food; “therefore, reduction of sodium is needed during processing for most foods.”
But the palatability of many foods is associated with salt as a flavour enhancer. Because of this there have been moves to reduce salt levels in food whilst keeping the intensity of salty tastes. This can be achieved through salt replacement substitutes, texture-taste interactions, and boosting intensity using flavour boosters or salty smells.
There are two main categories of salt replacers – potassium salts, and herbs and spices. Potassium salts can be used to reduce sodium intakes through direct replacement, however potassium is associated it has a bitter tastes and ‘off flavour’ formation. But, according to the researchers, herbs and other flavourings “could be a safer, tastier, and healthier alternative to salt.”
However they noted that although herbs and spices can substitute salt in the diet, they do not provide the salty taste; “therefore, it is necessary to develop healthier salt substitutes like herbs and spices that provide salty taste.”
Lee stated that the aim of this research was to develop a healthy, but intense tasting table salt substitute from plant extracts.
To develop the salt substitute with low sodium content, 13 plants were extracted and their sensory perception was analyzed. After the sensory evaluation, three plant aqueous extracts, representing salty and umami tastes, were selected and powdered using a spray dryer.
The three extracts, selected for their high salty taste were Saliornia herbacea L (saltwort), followed by Laminaria japonica (sea tangle), and then Lemtinus sedodes (mushroom).
These three extracts were subsequently mixed to make a plant salt substitute (PSS), which was then tested against sodium chloride for salt intensity and sodium levels.
The relative saltiness of the plant salt substitute to sodium chloride was found to be 0.65 – meaning that one per cent sodium chloride was equivalent in saltiness flavour intensity to 1.55 per cent of the plant salt substitute.
But, the sodium levels of PSS were observed to be almost one-third to that of sodium chloride, “As a result, the sodium level of PSS in similar saltiness is 57 per cent of that of sodium chloride.”
Prof Lee concluded that the spray-dried powders, collectively termed as plant salt substitute, may be used in processed foods to reduce sodium levels without reducing salty tastes that may influence consumer preferences.
Source: Food Research International
Published online ahead of print, doi: 10.1016/j.foodres.2010.11.018
“A Salt Substitute with Low Sodium Content from Plant Aqueous Extracts”
Author: G-H. Lee