The role of qualitative tests in detecting adulterants in stingless bee honey: A promising approach for honey producers and consumers

Among the hive products of stingless bees (SB), honey is distinguished because it has different physicochemical properties than the honey produced by Apis mellifera. Its taste is more acidic and less sweet, and it naturally contains a higher percentage of water. Honey is one of the most frequently adulterated products marketed. Therefore, this work aimed to verify if the qualitative tests performed for A. mellifera honey are also valid for SB honey from Tetragonisca angustula, Melipona quadrifasciata, and Tetragona elongata and if they can detect the most common adulterations. Adulterations of SB honey with corn syrup, inverted sugar, and A. mellifera honey were simulated and tested with Lugol, Fiehe, and Lund reactions. For these three analyses, sample volume reduction was also tested. The Lund test did not work well with honey samples from SB because they have a higher water content, and reliable results could not be obtained. For the other two tests, the sample volume reduction used was efficient. The Fiehe test detected adulteration with corn syrup only. The Lugol test detected corn syrup and inverted sugar adulterations in all dilutions for all three SB species. No adulteration by added water or honey from A. mellifera was detected in any test. Therefore, using the qualitative Lugol’s reaction test to evaluate SB honey quality is reasonably affordable. Since it is a rapid and inexpensive test, it allows the development of production chains for SB honey. Thus, detecting inauthentic honey can be done by combining qualitative tests as the first screening, followed by quantitative tests if necessary.