• Korean journal of food and cookery science
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• v.31 no.1
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• pp.62-71
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• 2015

The purpose of this study was to evaluate the changes on the characteristics of the oxidative stability of Tenebrio molitor larvae during cold storage at $4^{\circ}C$. Pretreatment for T. molitor larvae was designed into three methods: raw (R), freeze-dried (F.D.), and pan-fried (P.F.). The water content of the raw sample (61.46%) was higher than those of other samples (F.D.: 5.02%, P.F.: 3.67%) and its high water content was expected to facilitate the oxidation of the raw sample. In our results, the peroxide value and the carbonyl value of all of the samples increased and the raw sample, after storage for 18 day, showed the highest value. The pan-fried sample had no significant increase in its lactic acid content, acid value, and thiobarbituric acid value; whereas those values were increased in the raw sample and the freeze-dried sample (p<0.05). The browning reaction was more progressed in the pan-fried sample than other samples at 0 day, but there was no significant change during the storage. The raw sample and the freeze-dried sample had their browning indexes increase with the increasing storage period (p<0.05). The pan-fried sample produced less oxidation products than the freeze-dried sample, indicating that the unheated sample was more susceptible to oxidation than the heated samples. In conclusion, heating treatment and low water content would be effective for improving the safety and stability of T. molitor larvae during cold storage.

• Journal of Food Hygiene and Safety
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• v.36 no.1
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• pp.86-92
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• 2021

In order to utilize edible insect larvae as a functional material, the antioxidant components and activities of Tenebrio molitor larvae extracts were evaluated. The total phenolic content of the extract by ethanol concentration (95%, 70%, 50%, water) of T. molitor larvae powder was the highest in the 50% ethanol extract at 459.23 ± 1.05 mg%, and the total flavonoid content was the highest in the water extract at 19.86 ± 0.69 mg%. The DPPH radical scavenging activity of T. molitor larvae powder extract was the highest in 70% ethanol extract at 82.60 ± 0.00%, followed by water, 50% ethanol, and 95% ethanol extract. The ABTS radical scavenging activity in 50% ethanol and water extract was highest at 97.57 ± 0.16% and 95.33 ± 0.41%, respectively, with no significant difference. Significantly, the reducing power was the highest in water extracts, followed by 50%, 70%, and 95% ethanol extract. The results confirmed the antioxidant components and antioxidant activities of T. molitor larvae have been identified, indicating that it is worth using as a functional material.

• International Journal of Industrial Entomology and Biomaterials
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• v.32 no.1
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• pp.41-48
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• 2016

Mealworms, Tenebrio molitor (Coleoptera: Tenebrionidae), are widely used as food sourcefor animal rearing as well as human diet. Conventionally, mealworms raised on wheat bran. In this study, we investigated the effects of brewer's spent grain (BSG) on the growth of mealworm larvae to reduce the rearing cost. We prepared five different diets with various BSG content, 0, 10, 30, 50, and 70% of heated air dried BSG with wheat bran. We compared survivorship, larval weight, developmental duration, pupation rate, and pupal weight of five different groups of T. molitor raised on these five diets. The larval survivorships were almost similar with the control group except a group with 70% of BSG. For the larval weight, groups with 30% and 50% of BSG gained more weight than that with control treatment, 0% of BSG. For the developmental period, the groups with 30% of BSG took less time compared to the control group. In all treatment groups, more than 90% of pupation rate were observed. Especially, the group with 30% of BSG showed highest pupation rate among the five groups. Wheat bran with 30~50% of BSG was the optimal diet for successive insect rearing among the five diet treatments. Based on this study, we concluded that adding BSG to wheat bran helps to improve the quality of T. molitor and to reduce the rearing period.

• International Journal of Industrial Entomology and Biomaterials
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• v.28 no.1
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• pp.5-9
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• 2014

Tenebrio molitor is a major pest of stored grain, although its larvae have potential for use as food. However, little is known about the characteristics of individual larval instars of this species, and the number of instars remains disputed. Therefore, we assessed T. molitor for the average number of instars and its characteristics at different larval stages. The focus of this study was to establish a foundation for further studies on the characteristics of each larval instar. All of the T. molitor larvae showed incubation periods of 7 to 8 d and a period of 3 to 4 d for the $1^{st}$ instar. Beyond the $1^{st}$ instar, there were relatively large variations in the number of days in each instar period. Before emergence, most of the larvae had typically gone through 15 to 17 instars. The highest rate of pupae formation, 28.32%, was observed in the $17^{th}$ instars. The body length gradually increased with each successive instar, reaching its maximum at the 17th instar. Beyond the $17^{th}$ instar, however, the body length decreased. The larvae were white in the first instar, and gradually turned brown after the $2^{nd}$ instar.

• Journal of Life Science
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• v.28 no.8
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• pp.923-930
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• 2018

In this study, Tenebrio molitor (T. molitor) was fermented with Lactobacillus plantarum JBMI F3 (F3), Lactobacillus plantarum JBMI F5 (F5), Lactobacillus gasseri Ba9 (Ba9), Aspergillus kawachii KCCM 32819 (Ak), Saccharomyces cerevisiae KACC 93023 (Sc), and Bacillus subtilis KACC 91157 (Bs). After fermentation, the fermented products were extracted by water, ethanol, and methanol, and their physicochemical and biological properties were investigated. In a DPPH assay, the water extracts of the fermented products of T. molitor showed high antioxidant ability. Among the water extracts, the fermented product by Bs showed the highest DPPH radical scavenging activity. The total contents of phenolic compounds and flavonoids were highest in the fermented products by Ak and Bs, respectively. Reducing activity was detected the most high activity on ethanol extract of fermented product by Bs. The water extract of the fermented product by Bs exhibited strong enzymatic activity for fibrinogen and starch hydrolysis. Based on the observed physicochemical and biological properties, the fermented products of T. molitor by microorgansims can likely be applied as functional materials in various industries.

• Journal of Sericultural and Entomological Science
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• v.51 no.1
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• pp.9-14
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• 2013

Although the mealworm larva (Tenebrio molitor) is high protein source, aversion feature of the larva made it difficult for consuming as a food. In this study, we established optimal powder manufacturing process for T. molitor larva for using as a novel food. For this purpose, it should be feed with the bran sterilized by water vapor for 3-5 days, starved without water or food for 3 days, and then the larvae were sterilized before freeze-drying. The sterilized T. molitor was lyophilzed and grinded by a blender. A safety of the powder as a food was validated by evaluation of Raw 264.7 macrophage cytotoxicity using MTS assay. As above results, we propose that optimal powder manufacturing process established in this study can be used in industrial production of T. molitor as a novel food.

• Journal of Sericultural and Entomological Science
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• v.52 no.1
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• pp.73-78
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• 2014

This study was carried out to establish the self-specification and shelf-life by standardization of manufacturing process for Tenebrio molitor larvae. First, standardization of manufacturing process for T. molitor was set up. Sterilization for larvae placed on a multistage shelf with intervals of about 10 cm was carried out at $115^{\circ}C$, $1kgf/cm^2$ for 10 min. After sterilization, T. molitor larvae were frozen at less than $-35^{\circ}C$ for more than 12 hrs. And then, they were dried under $-15^{\circ}C$, 0.5 torr vacuum for more than 30 hrs. Second, we decided self-specification for T. molitor larvae. Their moisture, acidity, peroxide, crude protein and crude fat level should be 5% or less, 3 mg/g or less, 30 meq/g or less, 45% or more, and 25% or more, respectively. Also, oleic acid, representative material, level was set up 11 ~ 16%. Third, we decided shelf-life by analysis of the physicochemical characteristic, sensory evaluation and microbial indicators. The final expiry date for lyophilized T. molitor larvae in PET bottle was calculated as 12 months from date of manufacture. We expect that optimal manufacturing process system, self-specification, and shelf-life proposed in this study can be used in industrial production of T. molitor as a novel food.

• Food Science and Preservation
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• v.23 no.6
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• pp.890-898
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• 2016

The purpose of this paper is to investigate potential anti-inflammatory and anti-oxidant effects of Tenebrio molitor. Macrophage cell response by outside stimulation leads expression of pro-inflammatory cytokines, such as tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$), interleukin-6 (IL-6), $interleukin-1{\beta}$ ($IL-1{\beta}$), and trigger expression of genes which are affected by inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), resulting in formation of inflammatory factors like nitric oxide (NO) and Prostaglandin $E_2$ (PGE2). Cell viability was determined by MTT assay. In order to investigate anti-inflammatory agents, the inhibitory effects on the production of lipopolysaccharide (LPS)-induced NO in RAW 264.7 cells were examined. T. Molitor significantly decreased the production of NO in a dose-dependent manner, and also reduced the expression of iNOS, a COX-2 protein. As a result, the levels of protein such as $PGE_2$, iNOS, COX-2 and MARKs were significantly reduced compared to non-treated group in T. Molitor water extract (TDW) treated group. Also, antioxidant effect of T. Molitor were investigated using DPPH, ABTS+ and superoxide anion radical scavenging activity tests in cell-free system. Antioxidant activity of T. molitor was found low in the DPPH radical scavenging test while high in the ABTS+ and superoxide anion radical scavenging activity tests. These results show that TDW could be an effective anti-pro-inflammatory and anti-oxidant agent.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.421-429
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• 2016

Tenebrio molitor larvae contain large amounts of proteins, lipids and other functional materials, enabling this insect to be used as an edible food source in animal feeds and for industrialization. Although many efforts have been made to set up mass rearing systems, few studies have been conducted to establish optimal rearing conditions for the production of high quality T. molitor larvae. Herein we investigated 1) the effects of additional diets on the survival and fecundity of the insect, 2) the relationship between oviposition period and the uniformity of larval size, 3) the effects of rearing density and temperature on insect development, and 4) the storage stability of eggs and pupae at low temperatures given possible temporary production discontinuation. The addition of carrot and zucchini to the traditional wheat bran diet significantly increased the survival and fecundity rate of adult T. molitor. Of the three different oviposition sampling periods (3, 7, and 14 days) used to investigate the uniformity of the hatched larvae in each treatment, the period of 3 and 7 days provided higher uniformity than the 14 days oviposition period. Larval development was faster at $30^{\circ}C$ than at 20, 25, and $35^{\circ}C$. Interestingly, oviposition rates were highest at $20^{\circ}C$ but showed much slower larval development and lower uniformity at $30^{\circ}C$. Regarding the effect of larval rearing densities (1, 10, 20, 30, 40, and 50 larvae per 90 mm diam. dish), larval weight was significantly reduced at higher rearing densities, but larval longevity and length were not influenced by rearing density. The 30 larvae/dish is suggested to be a reasonable density to be applied to mass production systems. When kept at $4^{\circ}C$, T. molitor eggs showed a significant reduction in hatching rate; however, when stored under the same conditions, pupae emergence rates remained high until 10 weeks, suggesting that storage at low temperatures is more suitable for the pupal stage than the egg stage. Our findings suggest that an increase in T. molitor adult survival and fecundity rates and a uniformity of hatched larval development can be achieved with the following recommendations: a combination diet (including wheat bran), a 7-day oviposition period; a larvae-rearing temperature of $30^{\circ}C$, a rearing density of 30 larvae/dish, and the storage of pupal stages at low temperatures in the case of rearing discontinuation. This study serves as a strong foundation for the successful mass production of high quality T. molitor larvae.

• Journal of Life Science
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• v.27 no.3
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• pp.334-338
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• 2017

In this study, the nutritional components of Tenebrio molitor, Protaetia brevitarsis, and Allomyrina dichotoma larvae, which have been registered as novel foods, were analyzed and compared to expand the diversity of selection criteria for edible insects. The contents of crude components, amino acids, fatty acids, and minerals were analyzed. According to the results of comparative analysis of edible insects, crude proteins were abundant in all three kinds of insects. The content of crude fat was the highest in T. molitor, and the content of carbohydrate was the highest in A. dichotoma. When comparing the composition of amino acids, total amino acid content and essential amino acids were the highest in T. molitor larvae. In T. molitor and P. brevitarsis larvae, the compositions of fatty acids were similar, with higher amounts of unsaturated fatty acids than in A. dichotoma. In terms of mineral content, A. dichotoma contained the highest amounts of calcium and iron, whereas P. brevitarsis contained the highest amounts of phosphorus and potassium. With these results, it is expected that edible insects could be selected according to nutritional demand. In addition, multiple combinations of edible insects will offer a richer intake of nutrients.