Nutritional Value of Silkworm Pupae (Bombyx mori) with Emphases on Fatty Acids Profile and Their Potential Applications for Humans and Animals

Bombyx mori is an ideal lepidopteran species representative of many scientific studies, a model of studies for medicine and a significant insect from an ecological standpoint. This review was performed to summarize the fatty acids (FA) composition of silkworm pupae (SP) that are associated with other important compounds that could add value to SP, diversifying the ways of valorization. The proposal to complete plant-based feeds with insect-based feeds represents a viable option to beneficially impact human and animal health and the environment. The quality and quantity of fats consumed significantly impact the aetiology of certain diseases. The key compounds of fat named essential FA (EFA) substantially influence the prevention and treatment of several diseases through their nutraceutical functions. Due to its excellent profile in nutrients such as protein and fat, amino acids and fatty acids composition, SP has become an important alternative feed ingredient and source of EFA. SP is a by-product that was discarded in large quantities. Following the need to act to improve human health and reduce climate change impact, many researchers focused on studying SP applications in the medical and agricultural industries. Several authors noticed an improvement in the health markers by using SP. The feed cost for the animal was reduced with economic implications. Minimization of environmental impact was recorded. Few precautions were recommended regarding SP use, although they should not be ignored. The composition of SP and its potential for use in various industries provides us with persuasive arguments for continuing to develop the sericulture industry.

Facile acid fermentation extraction of silkworm pupae oil and evaluation of its physical and chemical properties for utilization as edible oil

Considering the increasing demand for edible oil in recent times, their price in the world market is becoming skyrocketing. In this research, we produced cost-effective edible oil from desilked silkworm pupae (Bombyx mori) applying a facile acid fermentation process, for the first time. The extraction was performed using two different types of organic acids, 3% of each acetic and citric acid. The yield of the extracted oil was 3.52 ± 0.23% from fresh silkworm pupae. The produced oil was then characterized physically and chemically to know its suitability to be used as edible oil. The oil was found with a low peroxide and acid value of 4.82 meq/kg and 1.35 mg KOH/g oil, respectively, and comprised of different fatty acids, in which palmitic acid (32.04%) and oleic acid (34.62%) were in large portions among the total fatty acids. Additionally, the extracted oil included linoleic, α-linolenic, and dihomo-gamma-linolenic acid which have health benefits. The oil was rich with minerals such as Iron, Sodium, Potassium, Calcium, Magnesium, Zinc, and Phosphorus with a negligible concentration of toxic elements such as Manganese, Cobalt, Nickel, Copper, Lead, Cadmium, Chromium, Arsenic, and Silver, indicating a good nutritive value of the extracted oil. Overall, the outcomes of all the characterizations showed that the extracted oil could be used as good edible oil and the corresponding acid fermentation extraction process has the potential to be used as an effective oil extraction method for silkworm pupae.

Characteristics and nutritional value of silkworm (Bombyx mori) pupae-fortified chicken bread spread

This study aimed to apply silkworm pupae (SP) to food product development. The characteristics and sensory acceptance of chicken bread spread fortified with SP at different levels (0%; SP0, 25%; SP25, 50%; SP50, and 75%; SP75) were evaluated. The fat content of the bread spread was significantly increased, whereas the protein content was decreased with increasing levels of SP (p ≤ 0.05). The increased level of SP resulted in the final products being dark in color, as indicated by the significant decrease in L* and the significant increase in a* and b* (p ≤ 0.05). SP50 was accepted by the consumer. Thereafter, the characteristics and sensory acceptance of SP50 with different levels of coconut oil (CO) (100%; SP50-100, 70%; SP50-70, 40%; SP50-40, and 10%; SP50-10 of CO content in the control sample) were studied. The firmness and stickiness increased, whereas TEF decreased with decreasing CO levels, which was related to the decreased spreadability of SP50. SP50-40 obtained satisfactory sensory properties by the consumer. The energy value for SP50-40 was within the normal range for bread spread products. Therefore, SP could be a source of fat and protein for the production of an alternative food product to increase the added value of edible insects.

Application of Aqueous Saline Process to Extract Silkworm Pupae Oil (Bombyx mori): Process Optimization and Composition Analysis

Silkworm pupae, a waste product from the silk production industry, can be an alternative source of edible oil, thus reducing the industry’s waste. In the present work, frozen silkworm pupae were used as raw material to extract oil via an aqueous saline process. The Box–Behnken design (BBD) and response surface methodology (RSM) were used to optimize the extraction process. The extraction conditions with the highest oil yield and a low peroxide value were obtained when using a saline solution concentration of 1.7% w/v, a ratio of aqueous liquid to silkworm pupae of 3.3 mL/g, and a 119 min stirring time at the stirring speed of 100 rpm. Under these conditions, silkworm oil with a yield of 3.32%, peroxide values of approximately 1.55 mM, and an acid value of 0.67 mg KOH/g oil was obtained. The extracted oil contained omega-3 acids (α-linolenic acid), which constituted around 25% of the total fatty acids, with approximate cholesterol levels of 109 mg/100 g oil. The amounts of β-carotene and α-tocopherol were approximately 785 and 9434 μg/100 g oil, respectively. Overall, the results demonstrated that oil extracted from silkworm pupae has good quality parameters and thus can be used as a new valuable source of edible lipids.

Fatty acid profile, minor bioactive constituents and physicochemical properties of insect-based oils: A comprehensive review

Insect-based food or ingredients have received tremendous attention worldwide because of their potential to ensure food and nutrition security, mitigating the reliance on land-dependent agricultural products. Indeed, insect-farming has low environmental impacts with reduced land, water and energy input. More importantly, insects are rich in high quality proteins and fats. They are also excellent sources of minerals, vitamins and bioactive compounds. Insect-based lipids are intriguing because they may contain high levels of unsaturated fatty acids particularly linoleic and α-linolenic acids. Besides, the insect-based lipids also show a considerable amount of bioactive components such as tocols, sterols and carotenoids. However, their fatty acid compositions and the nutritional values may vary depending on species, feed composition, developmental stage, geographical locations, and extraction techniques. Therefore, the present article aims to provide a comprehensive review on the fatty acid composition, the minor bioactive constituents and the physicochemical properties of fats and oils derived from insects of different orders (Coleoptera, Lepidoptera, Hymenoptera, Orthoptera, Hemiptera and Diptera). The various parameters affecting the nutritional compositions of the insect-based lipids will also be highlighted. These information will definitely provide a detailed insight on the potential applications of these fats in various food systems based on their unique properties.

Synthesis and Characterization of Epoxidized Silkworm Pupae Oil and Its Application as Polyvinyl Chloride

More and more industries demand environmental friendliness. Silkworm pupae oil (SPO), extracted from the desilked silkworm pupae, can serve as a promising substrate alternative to use in plasticization. This study aimed to prepare epoxidized silkworm pupae oil (ESPO) and investigate their effects on the thermal stability and plasticization of polyvinyl chloride (PVC) films. A chemo-enzymatic method of ESPO was developed in the presence of Lipase SMG1-F278N and H₂O₂ in natural deep eutectic solvents (DESs). Lipase SMG1-F278N could initiate the epoxidation reaction effectively at room temperature with a negligible loss of activities 10 batches. A maximum oxirane value of 6.94% was obtained. The formation of oxirane ring in ESPO was confirmed by FTIR and ¹³C NMR spectra. Moreover, ESPO showed a better thermal stability and lower freezing point than epoxidized soybean oil (ESO). It was demonstrated that ESPO had a good frost resistance. In addition, ESPO showed a significantly improved plasticizing effect on flexible polyvinyl chloride (PVC). Compared with ESO, ESPO could increase the tensile elongation at break effectively. A significantly lower migration rate of plasticizer was observed in PVC plasticized with ESPO.

Nutritional, functional, and allergenic properties of silkworm pupae

Edible insects are a food source that has high nutritional value. Domestic silkworm pupae are an important by-product of sericulture and have a long history as food and feed ingredients in East Asia. Silkworm pupae are a good source of protein, lipids, minerals, and vitamins and are considered a good source of nutrients for humans. Silkworm pupae are a valuable insect source of substances used in healthcare products, medicines, food additives, and animal feed. Because silkworm pupae are being increasingly used in the human diet, potential allergic reactions to the substances they contain must be elucidated. Here, we present an overview of the benefits of silkworm pupae. First, we describe their nutritional value. Second, we report their functional properties and applications, focusing on their potential use in the food and pharmaceutical industries. Finally, we consider the current state of research regarding silkworm pupae-induced allergies.

Chemical Composition, Nutrient Quality and Acceptability of Edible Insects Are Affected by Species, Developmental Stage, Gender, Diet, and Processing Method

Edible insects have been considered as either nutritious food itemsper se, or as wholesome ingredients to various dishes and components of traditional subsistence. Protein, fat, mineral and vitamin contents in insects generally satisfy the requirements of healthy food, although there is considerable variation associated with insect species, collection site, processing method, insect life stage, rearing technology and insect feed. A comparison of available data(based on dry weight) showed that processing can improve the nutrient content, taste, flavour, appearance and palatability of insects, but that there are additional factors, which can impact the content and composition of insect species that have been recommended for consumption by humans. This review focuses on factors that have received little attention in connection with the task to improve acceptability or choice of edible insects and suggests ways to guarantee food security in countries where deficiencies in protein and minerals are an acute and perpetual problem. This review is meant to assist the food industry to select the most suitable species as well as processing methods for insect-based food products.

A Lipidome Map of the Silkworm Bombyx mori: Influences of Viral Infection

Lipids have been recently proposed as key molecules for virus entry and egress, and lipid biosynthesis and signaling were reported necessary for some viruses during replication and infection. The silkworm Bombyx mori is an important economic insect and a model organism, but its lipid profiles have not been systematically investigated. Most silkworm strains are susceptible to the B. mori nuclear polyhedrovirus (BmNPV), a baculovirus that causes serious loss to the sericulture industry. Previously, our lab has screened a natural mutant of B. mori that is highly resistant to BmNPV. In this study, a comprehensive lipidomic analysis by ultrahigh pressure liquid chromatography-mass spectrometry (UPLC-MS) was carried out on the BmNPV-susceptible strain 306 and resistant strain NB (data deposited in MetaboLight MTBLS2142). Comparisons of the lipid profiles between the two strains reveal that phosphosphingolipids, diacylglycerolipids, ceramides, and quinones were present at notably higher levels in the susceptible strain, while lysophosphocholines were found at a higher level in the resistant strain. BmNPV administration changed the lipid profiles in both strains, revealing key lipids involved in virus infection and immune response. Some key enzymes in the lipid biosynthesis pathway were analyzed for their activities in the two silkworm strains and their virus-administered counterparts, underlining the relation among lipid biosynthesis, viral resistance, and immune response in the host.

The digestion of galactolipids and its ubiquitous function in Nature for the uptake of the essential α-linolenic acid

Galactolipids, mainly monogalactosyl diglycerides and digalactosyl diglycerides are the main lipids found in the membranes of plants, algae and photosynthetic microorganisms like microalgae and cyanobacteria. As such, they are the main lipids present at the surface of earth. They may represent up to 80% of the fatty acid stocks, including a large proportion of polyunsaturated fatty acids mainly α-linolenic acid (ALA). Nevertheless, the interest in these lipids for nutrition and other applications remains overlooked, probably because they are dispersed in the biomass and are not as easy to extract as vegetable oils from oleaginous fruit and oil seeds. Another reason is that galactolipids only represent a small fraction of the acylglycerolipids present in modern human diet. In herbivores such as horses, fish and folivorous insects, galactolipids may however represent the main source of dietary fatty acids due to their dietary habits and digestion physiology. The development of galactolipase assays has led to the identification and characterization of the enzymes involved in the digestion of galactolipids in the gastrointestinal tract, as well as by microorganisms. Pancreatic lipase-related protein 2 (PLRP2) has been identified as an important factor of galactolipid digestion in humans, together with pancreatic carboxyl ester hydrolase (CEH). The levels of PLRP2 are particularly high in monogastric herbivores thus highlighting the peculiar role of PLRP2 in the digestion of plant lipids. Similarly, pancreatic lipase homologs are found to be expressed in the midgut of folivorous insects, in which a high galactolipase activity can be measured. In fish, however, CEH is the main galactolipase involved. This review discusses the origins and fatty acid composition of galactolipids and the physiological contribution of galactolipid digestion in various species. This overlooked aspect of lipid digestion ensures not only the intake of ALA from its main natural source, but also the main lipid source of energy for growth of some herbivorous species.

Sensing Exposure Time to Oxygen by Applying a Percolation-Induced Principle

The determination of food freshness along manufacturer-to-consumer transportation lines is a challenging problem that calls for cheap, simple, reliable, and nontoxic sensors inside food packaging. We present a novel approach for oxygen sensing in which the exposure time to oxygen-rather than the oxygen concentration per se-is monitored. We developed a nontoxic hybrid composite-based sensor consisting of graphite powder (conductive filler), clay (viscosity control filler) and linseed oil (the matrix). Upon exposure to oxygen, the insulating linseed oil is oxidized, leading to polymerization and shrinkage of the matrix and hence to an increase in the concentration of the electrically conductive graphite powder up to percolation, which serves as an indicator of food spoilage. In the developed sensor, the exposure time to oxygen (days to weeks) is obtained by measuring the electrical conductivity though the sensor. The sensor functionality could be tuned by changing the oil viscosity, the aspect ratio of the conductive filler, and/or the concentration of the clay, thereby adapting the sensor to monitoring the quality of food products with different sensitivities to oxygen exposure time (e.g., fish vs grain).

Free radical scavenging and tyrosinase inhibition activity of oils and sericin extracted from Thai native silkworms (Bombyx mori)

Oils and sericin were extracted from pupae and silk cocoons, respectively, of the five Thai native silkworms (Bombyx mori, Linnaeus (Bombycidae)), namely, Keawsakol, Nangnoi, Somrong, Nangleung, and Noneruesee, which are variations of the same species. The oils were extracted by a hot process using Soxhlet apparatus and a cold process using petroleum ether, while sericin was extracted by basic hydrolysis and autoclaving. Sericin from the five Thai native silkworms showed free radical scavenging activity lower than the standard antioxidants (vitamin C, vitamin E, and BHT) by about 20-100-fold, but all oils gave higher activity than that of the standard linoleic acid by 11-22-fold. Oil extracted from Noneruesee by the cold process gave the highest DPPH scavenging activity, compared with other oil samples. All sericin samples showed tyrosinase inhibition activity with IC(50) values in the range of 1.2-18.76 mg/mL, but only oils from Noneruesee extracted by the hot process, and Nangleung, Somrong, and Noneruesee extracted by the cold process, showed this activity. Oil extracted by the hot process and sericin by basic hydrolysis from Noneruesee gave the highest tyrosinase inhibition activity, but lower than that of the standards vitamin C and kojic acid by 20-49 and 3-8 times, respectively. This study has suggested that sericin and oil from Noneruesee extracted by basic hydrolysis and the cold process, which gave the highest tyrosinase inhibition and free radical scavenging activity, respectively, can be applied in antiaging and whitening cosmetic products.

Optimization of supercritical carbon dioxide extraction of silkworm pupal oil applying the response surface methodology

Supercritical carbon dioxide extraction (SC-CO(2)) of oil from desilked silkworm pupae was performed. Response surface methodology (RSM) was applied to optimize the parameters of SC-CO(2) extraction. The effects of independent variables, including pressure, temperature, CO(2) flow rate, and extraction time, on the yield of oil were investigated. The statistical analysis showed that the pressure, extraction time, and the quadratics of pressure, extraction time, and CO(2) flow rate, as well as the interactions between pressure and temperature, and temperature and flow rate, showed significant effects on oil yield. The optimal extraction condition for oil yield within the experimental range of the variables researched was at 324.5 bar, 39.6 degrees C, 131.2 min, and 19.3 L/h. At this condition, the yield of oil was predicted to be 29.73%. The obtained silkworm pupal oil contained more than 68% total unsaturated fatty acids, and alpha-linolenic acid (ALA) accounted for 27.99% in the total oil.