Impact of thermal processing on physicochemical properties of silk moth pupae (Bombyx mori) flour and in-vitro gastrointestinal proteolysis in adults and seniors

Potential uses of silkworm pupae (Bombyx mori L.) in food, feed, and other industries: a systematic review

The increasing pressures imposed on ecosystems by the growing needs of the human population are stimulus for research into innovative and unconventional sources of raw materials for different industries. This systematic review was carried out to investigate the available literature on the possible industrial uses of silkworm (Bombyx mori L.) pupae, a residue of silk production. The review was conducted using an adapted version of PRISMA. After a screening process, 105 articles were obtained and subjected to a detailed quantitative and qualitative analysis. It was found that in the last decade there has been a significant increase in the number of papers devoted to the study of the potential use of silkworm pupae in different applications, with a significantly higher number in the last three years of the scope of this review, indicating a growing interest in the subject. From the analysis of the information collected, promising uses in human and animal food, such as fish, mammalian, poultry, swine and companion animals, as well as potential uses for the pharmaceutical industry, were identified. The evaluated research identified compounds with antioxidant activity and important contents of unsaturated fatty acids, which are related to beneficial effects on cardiovascular health, diabetes control, reduction of the risk of developing certain types of cancer and inflammatory activity, among other benefits. One of the most relevant findings is that many studies report a significant concentration of α-linolenic acid in silkworm pupae oil, which is attributed with anticancer, anti-inflammatory, antioxidant, anti-obesity and neuroprotective properties, among others.

Simultaneous Extraction of Oil and Protein from Silkworm (Bombyx mori L.) Pupae (Lueng Parroj var.) and Their In Vitro Skin Moisturization

Oil and protein from silkworm (Bombyx mori var. Leung Pairoj) pupae, by-product from sericulture, were extracted and evaluated for their potential uses as skin biomoisturizer. The silkworm pupae (SWP) oil and protein were simultaneously extracted by using three-phase partitioning (TPP) method and determined for their physicochemical properties including fatty acid and amino acid content, respectively. The highest yields of oil and protein at 8.24 ± 0.21% and 8.41 ± 0.26% w/w, respectively were obtained from 18 h extraction. Fatty acid analysis of SWP oil was rich in linolenic acid (37.81 ± 0.34%), oleic acid (28.97 ± 0.13%), palmitic acid (21.27 ± 0.05%), stearic acid (6.60 ± 0.09%) and linoleic acid (4.73 ± 0.21%). The clear yellow SWP oil possessed saponification value of 191.51 mg/g, iodine value of 119.37 g I2/g and peroxide value of 2.00 mg equivalent O2/kg. The SWP protein composed of 17 amino acids which aspartic acid, glutamic acid, glycine and serine were the major residues. SDS-PAGE analysis revealed that the SWP protein consisted of distinct protein at around 51, 70, 175 and over 175 kDa. Cytotoxicity of the SWP oil and protein was evaluated by using MTT assay and they showed low cytotoxicity toward keratinocyte cell (HaCat cell line). The SWP oil provided moisturizing effect on pig skin comparable to olive oil, while 1% and 2% of SWP protein showed higher moisturizing efficacy than 3% hydrolyzed collagen. The study indicated that the SWP oil and protein could be potential biomoisturizers for cosmetic products.

Nutritional Composition of Bombyx mori Pupae: A Systematic Review

Simple Summary

The mulberry silkworm (Bombyx mori) is a domesticated insect traditionally reared to produce silk. Its pupae are historically eaten in Asian countries and are obtained as waste products from the silk reeling industry. Pupae are a promising novel food in Western countries as well as a source of proteins, lipids, and minerals. Several varied results are reported in the literature regarding the nutrient composition of silkworm pupa, and several factors must be considered when comparing the research. Some of the variables that could affect the pupal nutritional content include rearing techniques, diets, silkworm strains, killing, and drying techniques. This literature systematic review identifies the most important research areas and aids authorities and producers in the evaluation and development of silkworm pupae for novel uses.

Abstract

As insects have started to enter the eating habits of Western countries, an increasing amount of literature regarding the mulberry silkworm (Bombyx mori) prospective application as food has been published. Despite this growing interest, there is currently no systematic review of silkworm nutritional composition available. In this paper, we performed a systematic review of the recent available literature on the nutrient composition of mulberry silkworm pupae. After screening the titles and abstracts of 14,008 studies retrieved from three scientific databases, data about nutrients was extracted from 29 selected papers, together with their related variables. This systematic review provides an overview of the variety of data reported in the literature and highlights that many elements contribute to hindering a sound comparison of the different nutritional values reported for silkworm pupae. The observed variability of the composition data reported could be due to differences in diet, strains, pretreatments, and origin of the silkworm analyzed. However, all these variables were not always available and should be reported in future studies to simplify the data comparison.

Understanding protein digestion in infants and the elderly: Current in vitro digestion models

The last decades have witnessed a surge of interest in the fate of dietary proteins during gastrointestinal (GI) digestion. Although several in vitro digestion models are available as alternatives to clinical experiments, most of them focus on the digestive conditions of healthy young adults. This study investigates the static/dynamic models used to simulate digestion in infants and the elderly and considers the related in vivo conditions. The in vitro digestive protocols targeting these two groups are summarized, and the challenges associated with the further development of in vitro digestion models are discussed. Static models rely on several factors (e.g., enzyme concentration, pH, reaction time, and rotation speed) to differentiate digestive conditions depending on age. Dynamic models can more accurately simulate the complex digestion process and allow the inclusion of further parameters (sequential secretion of digestive fluids, gradual changes in pH, peristaltic mixing, GI emptying, and the inoculation of luminal microbiota). In the case of infants, age or growth stage clarification and the differentiation of digestive protocols between full-term and preterm infants are required, whereas protocols dealing with various health statuses are required in the case of the elderly, as this group is prone to oral cavity and GI function deterioration.

Effect of the silkworm pupa protein-glucose conjugate on the thermal stability and antioxidant activity of anthocyanins

Anthocyanin (cyanidin-3-O-glucose) is a natural water-soluble pigment with a robust antioxidant capacity. However, its poor stability and bioavailability limits its application as a functional food ingredient. This study explored the ability of the silkworm pupa protein-glucose (Spp-Glu) conjugate, developed under wet-heating conditions, to improve the thermal stability and antioxidant activity of cyanidin-3-O-glucose (C3G) at pH 3.0 and 6.8. The characterization experiments suggested that C3G complexed with the Spp-Glu conjugate could modify the protein's microenvironment and cause unfolding of the protein's secondary structures under varied pH conditions. Spectroscopic techniques further revealed the formation of complexes via hydrophobic interactions and static quenching processes when C3G was bound to Spp or Spp-Glu. The formation of these complexes effectively attenuated C3G degradation, thereby enhancing its stability under heat treatment over a range of pH values, and the experiments measuring antioxidant activity suggested that the Spp-Glu conjugate formed does not affect the efficacy of C3G after complexation. Therefore, our study suggests that Spp-Glu has the potential to effectively protect and deliver anthocyanins during industrial application for functional food formulation.