Ochratoxin A (OTA) is one of the most important mycotoxins owing to its widespread occurrence and toxicity including nephrotoxicity and potential carcinogenicity to humans. Since OTA is stable under most food processing conditions, OTA has been detected not only in a wide range of agricultural commodities such as cereal grains but also their processed products. Nonetheless, it is known that significant reduction of OTA may be achieved under higher temperature and alkaline conditions. In this study, the effects of retorting cooking process on the stability of OTA in spiked (20 μg/kg of dry weight basis) rice and oat porridge (10% solid content; w/v) in the presence and absence of baking soda was investigated using a laboratory horizontal steam retort system. The samples were heated in a pot at 85°C central temperature until it becomes gelatinized, packed in retort pouched, and heat-processed in pressurized retort machine (at 121°C for 25 min) followed by drying in 50°C oven overnight. Samples were analyzed for OTA by high-performance liquid chromatography with a fluorescence detector (HPLC-FLD). The reduction of OTA in retorted rice and oat porridge were 54% and 17%, respectively, while greater reduction of OTA was observed at increased amount of baking soda. The reduction of OTA in retorted rice porridge with 0.5% and 1% baking soda were 55% and 66%, respectively. In the retorted oat porridge, reduction of OTA was also evident to result in 30% and 48% with 0.5% and 1.0% of added baking soda, respectively. These results suggest that OTA in rice and oat may be reduced significantly by retorting process. In addition, added baking soda may positively impact the reduction of OTA.

Ochratoxin A (OTA) represents one of the most widespread mycotoxins in agricultural commodities in the world and is considered a possible human carcinogen with its potent nephrotoxicity. Since OTA is stable under most food processing conditions, OTA has been detected in a wide range of cereal grains and their processed products as well. Puffed cereals are commonly used as baby snacks or as ingredients in snack formulations. We investigated the explosive puffing process effect on reduction of OTA in rice and oat. The rice and oat grains were adjusted the moisture content at 16% wet weight basis (wb) and spiked OTA (100 μg/kg), and then puffed by the explosive puffing machine at 5, 7, and 9 kgf. The temperature of chamber was 200°C and the duration times for 5, 7, and 9 kgf were 5, 6, and 9 min, respectively. The reduction of OTA in puffed rice and oat snacks were in the range of 15 – 28% and 38 – 52%, respectively, and the reduction of OTA in puffed rice and oat snacks were decreased with increasing explosive puffing pressures. The moisture content of puffed rice and oat snacks were in the range of 5 – 8% wb and 6 – 10% wb, respectively, and the moisture content in puffed rice and oat snacks were decreased with increasing of explosive puffing pressures. A decrease in bulk density of puffed rice and oat snacks was observed with increased explosive puffing pressure. In addition, increased values of degree of redness (a) in puffed rice and oat samples were observed with increasing explosive puffing pressure. These results suggest that OTA in rice and oat may be reduced significantly by explosive puffing process.

Ochratoxin A, which is frequently detected in cereals and infant diets worldwidely, is a mycotoxin to damage mainly the kidney and liver. Because ochratoxin A is highly thermostable compound. it is necessary to study ways of reducing level of ochratoxin A by controling processing steps. However, food processes, including extrusion, expansion, roasting, and steam cooking, which are used in order to mitigate the contents of ochratoxin A, are known to produce polycyclic aromatic hydrocarbons, which are generated from radicals decomposed by pyrolysis. Therefore, this study analyzed the levels of 4 polycyclic aromatic hydrocarbons, benz (a) anthracene, chrysene, benzo (b) fluoranthene and benzo (a) pyrene in rice-based products made in high pressure and heating process. Rice samples were finely ground, and homogenized samples were alkaline treatement with 1 M KOH/EtOH and extracted with liquid-liquid extraction method using n-hexane. The extracted solution was pretreated with a silica cartridge. The purified solution was dried with nitrogen gas and dissolved in 1 mL of dichloromethane and injected into GC/MSD. We had overall recoveries for 4 polycyclic aromatic hydrocarbons spiked into rice samples ranging from 92.8 to 110.2%. The limit of quantitations of benz (a) anthracene, chrysene, benzo (b) fluoranthene and benzo (a) pyrene in rice-based product were 0.19 ng/g, 0.38 ng/g, 0.51 ng/g, and 0.31 ng/g, respectively. However, these 4 polycyclic aromatic hydrocarbons in all processed rice samples were not detected.

Ochratoxin A (OTA) is one of the most important mycotoxins due to its prominent nephrotoxicity as well as potential carcinogenicity to human. OTA has been detected in a wide range of agricultural commodities including cereal grains and their processed products. OTA is stable under most food processing conditions while the reduction of OTA is more rapid and extensive under higher temperature and alkaline conditions. In this study, the effects of extrusion cooking on the stability of OTA in spiked (100 μg/kg) rice flour (moisture content, 16% wet weight basis) in the presence and absence of baking soda was investigated using a laboratory scale twin-screw extruder. The extrusion variables were temperature (120 and 150°C), screw speed (150, 200, and 250 rpm), and baking soda (0, 0.5, and 1%, w/w). Both unextruded and extruded samples were analyzed for OTA by high-performance liquid chromatography with a fluorescence detector (HPLC-FLD). The reduction of OTA was in the range of 78-82% with no added baking soda, whereas lesser reductions of 75-80% and 72-77% were observed at 0.5% and 1% baking soda, respectively. Both temperature and screw speed did not affect reduction of OTA during extrusion regardless of the presence or absence of baking soda. While the total color difference (ΔE) of extruded samples were increased with baking soda content, the radial expansion of extruded samples were decreased with baking soda content. These results suggest that OTA in rice flour may be reduced significantly by extrusion. In addition, added baking soda may negatively impact the reduction of OTA while its mechanism of action is unknown.