Recognition of the Duration and Prediction of Insect Prevalence of Stored Rough Rice Infested by the Red Flour Beetle (Tribolium castaneum Herbst) Using an Electronic Nose

The purpose of this research is to explore the feasibility of applying an electronic nose for the intelligent monitoring of injurious insects in a stored grain environment. In this study, we employed an electronic nose to sample rough rice that contained three degrees of red flour beetle (Tribolium castaneum Herbst) infestation for different durations—light degree (LD), middle degree (MD), and heavy degree (HD)—and manually investigated the insect situation at the same time. Manual insect situation investigation shows that, in all three rice treatments, the insect amounts gradually decreased after infestation. When the insect population of stored rough rice was under 13 insects per 60 g of rough rice, the natural speed of decrease of the insect population became very slow and reached the best artificial insect killing period. Linear discriminant analysis (LDA) provided good performance for MD and HD insect harm duration identification, but performed poorly for LD insect harm duration identification. Both k-means clustering analysis (K-means) and fuzzy c-means analysis (FCM) effectively identified the insect harm duration for stored rough rice. The results from the back-propagation artificial neural network (BPNN) insect prevalence prediction for the three degrees of rough rice infestation demonstrated that the electronic nose could effectively predict insect prevalence in stored grain (fitting coefficients were larger than 0.89). The predictive ability was best for LD, second best for MD, and least accurate for HD. This experiment demonstrates the feasibility of electronic noses for detecting both the duration and prevalence of an insect infestation in stored grain and provides a reference for the intelligent monitoring of an insect infestation in stored grains.

Simultaneous decontamination and drying of rough rice using combined pulsed light and holding treatment

BACKGROUND

Pulsed light (PL) technology has been proven effective in food disinfection. However, increasing the light intensity or treatment time could swiftly increase the temperature of the food product. Using the thermal effect in an appropriate way may achieve a simultaneous disinfection and drying effect. The objective of this study was to investigate the feasibility of simultaneous disinfection and drying of rough rice using PL and holding treatment.

RESULTS

Freshly harvested rice samples were inoculated by Aspergillus flavus (A. flavus) and treated using PL under different intensities and durations followed by holding treatment. The PL treatment under intensity of 1.08 W cm(-2) for 21 s led to a reduction of 0.29 log cfu g(-1) on the population size of A. flavus spores. After holding treatment, a 5.2 log cfu g(-1) reduction was achieved. The corresponding total moisture removal reached 3.3% points. No adverse effect on milling quality was detected after the treatment.

CONCLUSION

The obtained results revealed that the combined PL and holding treatment had good potential for successful application in the rice industry to simultaneously achieve disinfection and drying. © 2015 Society of Chemical Industry.

Soaking and extrusion effects on physicochemical parameters, phytic acid, nutrient content and mineral bio-accessibility of whole rice grain

A combination of soaking and extrusion processes of whole rice grain was studied. The effects of temperature (35-55 °C) and time (24-48 h) of soaking treatment on phytic acid (PA), protein and ashes losses using a factorial design were evaluated. Taking into account ash, protein and PA losses, whole rice was soaked 24 h at 45 °C and extruded using a Brabender single screw extruder. Effects of extrusion temperature (160-190 °C) and moisture content (14-19 g/100 g) on product characteristics were evaluated using surface response methodology. Values corresponding to the different responses were: Expansion (1.64-3.28), Specific Volume (5.68-11.06 cm(3)/g), Water absorption (3.41-4.43 mL/g) and Solubility (45.44-66.20 g/100 g). The content of PA was reduced from 740.09 to 163.47 mg/100 g (77%) after both processes, resulting in a higher mineral bio-accessibility, and a 7.3% decrease of protein digestibility. Total soluble phenolics and trolox equivalent antioxidant capacity (TEAC) were affected according to the treatment. Both treatments were important to obtain a nutritionally improved whole grain product.