Resistance of Rice Varieties to the Stored-Product Insect, Sitophilus zeamais (Coleoptera: Curculionidae).

Four common Portuguese rice varieties--Thaibonnet, Gladio, Albatros, and Eurosis--were tested for their relative susceptibility to Sitophilus zeamais Motschulsky, a common pest of stored rice in Portugal and in tropical countries. Physical (moisture content, hardness, length, and width) and chemical (by attenuated total reflection-Fourier transform infrared spectroscopy) properties of rice kernels were measured. Insect bioassays measured median developmental time, Dobie's index of susceptibility, percentage of damaged grains and weight loss, and progeny developed. This was done for paddy, brown rice, and polished rice for each variety. There were small, but significant, differences in insect resistance among the varieties. However, it was different for paddy and polished rice. In paddy, these differences were correlated with hull damage, and Eurosis was the most susceptible variety. In polished rice, resistance was correlated with hardness, and Thaibonnet was the most susceptible variety. In general, paddy rice was more resistant to insect attack, followed by polished rice and then brown rice. Paddy kernels selected with undamaged hull were completely resistant to attack. Implications for IPM and breeding for resistant varieties are discussed.

Development of Healthy Snacks Incorporating Meal from Tenebrio molitor and Alphitobius diaperinus Using 3D Printing Technology.

This study analyzes the nutritional properties of edible insects, specifically Tenebrio molitor and Alphitobius diaperinus, and explores the potential of 3D printing technology to introduce a nutritious and tasty alternative to essential nutrients for Western consumers. An original formulation for the printing of snacks with microalgae was adapted to incorporate edible insects. Concentrations of 10% of edible insects, both isolated and mixed, were incorporated into the developed ink-doughs. Stress and frequency sweeps were performed on the doughs to understand the rheology and the impact on the internal structure to better adapt these materials to the 3D printing process. The nutritional profile of the developed snacks was assessed, revealing a significant amount of protein, enough to claim the snacks as a "source of protein", as well as an increased mineral profile, when compared to the control snack. The antioxidant profile and total phenolic content were equally assessed. Finally, a sensory analysis test was performed, comparing the control snack to three other samples containing 10% T. molitor, 10% A. diaperinus and 5% + 5% of T. molitor and A. diaperinus, respectively, resulting in a preference for the A. diaperinus and for the combination of the two insects. Considered as a "novel food", foods incorporating edible insects represent, in fact, the reintroduction of foods used in the West before the Middle Ages, when the Judeo-Christian tradition began to consider insects as not kosher. Educating consumers about the transition to novel foods can be helped by 3D printing food, as an innovative process that can be used to design creative rich animal protein snacks that make final products more appealing and acceptable to consumers.

Development of Healthy Protein-Rich Crackers Using Tenebrio molitor Flour.

Entomophagy is still a widespread practice in Africa and Asia, although it is declining due to the westernization of diets. Today, the issue of its rehabilitation is underway; indeed, the nutritional economic and ecological stakes of this consumption are strategic. It can be considered an important way to face the scarcity of natural resources, environmental pressures due to the increasing world population, and demand for protein. Tenebrio molitor larvae flour was recently approved by the European Food Safety Authority (EFSA) as a novel food. The aim of the present work was to create protein-rich healthy cracker from insect flour, achieving the claim "source of protein" with a target market focused on the healthy products for consumption on the go. Contents of T. molitor flour from 2 to 20% (%w/w) were tested, using a previously optimized formulation and the comparison in terms of nutritional, physical, and sensory properties with a standard formulation was performed. T. molitor incorporation allowed an improvement in the nutritional profile of snacks, through an increase of 15% in protein content and an enrichment in minerals (namely potassium, phosphorus, copper, and zinc). The crackers containing a 6% of insect flour were the most appreciated by the panelists. The incorporation of T. molitor induced a reduction in firmness and an increase in crispness, resulting from the impact of the protein on the structure. This aspect has a positive impact with respect of the acceptance of snacks-70% of the panelists consider the possibility to buy the crackers with 6% enrichment. A darkening of the samples with the increase in the incorporation of T. molitor flour was also observed, accompanied by a reduction of about 20% of the L* values. Globally, insect protein can play an important role in redesigning food diets, making them more sustainable, with less environmental impact and equally balanced.

Antifungal Activity of Benzoquinones Produced by Tribolium castaneum in Maize-Associated Fungi.

Tribolium castaneum (Herbst) adults produce 1,4-benzoquinone (BQ), methyl-1,4-benzoquinone (MBQ), and ethyl-1,4-benzoquinone (EBQ). These components are chemical defenses used as repellents and irritants, and BQ has a negative impact on the growth of some fungal species. In this work, the inhibitory and/or lethal effects of these benzoquinones on the development of six fungi identified in maize, namely Aspergillus flavus, A. fumigatus, A. niger, Fusarium sp., Penicillium sp., and Trichoderma sp., were evaluated. Ten-day-long disk diffusion trials were performed using benzoquinones. The experiments simulated the activity of BQ (B1) or "EBQ + MBQ" (B2) released by 40-day-old insect adults (n = 200), considering a total average release of 45 µg per adult. Inhibition halos imposed by benzoquinones on fungal growth showed a significant effect when compared with the controls (water and solvent). Mycelial growth was decreased for all fungi, with the level of response depending on the fungal species. B1 and B2 displayed an inhibitory effect against all fungi, but Trichoderma sp. and A. niger showed rapid recoveries. B2 showed a lethal effect on Penicillium sp. The inhibitory and lethal activities of benzoquinones released by T. castaneum adults may contribute to regulate fungal growth, and understanding their interaction is important to develop innovative control strategies.

The Interaction between Tribolium castaneum and Mycotoxigenic Aspergillus flavus in Maize Flour.

Tribolium castaneum is one of the most common insect pests of stored products. Its presence makes cereals more susceptible to the spread of the fungi Aspergillus flavus, which may produce mycotoxins. The aim of this work was to evaluate the influence of T. castaneum adults on the development of a mycotoxigenic A. flavus strain in maize flour as well as the influence of this fungus on the insects. Maize flour was exposed to T. castaneum, spores of A. flavus or to both. The results revealed an interaction between T. castaneum and A. flavus as the flour exposed to both organisms was totally colonized by the fungus whereas almost all the insects were killed. Aflatoxin B1 (AFB1) revealed a significantly higher concentration in the flour inoculated with both organisms (18.8 µg/kg), being lower when exposed only to A. flavus, suggesting that the presence of insects may trigger fungal development and enhance mycotoxin production. The ability of these organisms to thrive under the same conditions and the chemical compounds they release makes the interaction between them a subject of great importance to maintain the safety of stored maize. This is the first work evaluating the interaction between T. castaneum and A. flavus mycotoxin production.