Effects of flaxseed cake fortification on bread shelf life, and its possible use as feed for Tenebrio molitor larvae in a circular economy: preliminary results.

BACKGROUND: Bread represents a significant share of food waste worldwide. The extension of the bread shelf life together with innovative systems of food waste treatment might decrease waste biomass decay, the need for transportation, and the need for storage. In recent years, insects have been selected as a valuable tool for food waste treatment owing to their capability to transform low-value food waste into biomass with high nutritional value. Bakery wastes can be used profitably for this purpose. This work had two objectives: (i) to measure the impact of flaxseed cake fortification on bread shelf life depending on the leavening agent (baker's yeast vs sourdough); (ii) to evaluate the possible reuse of the stale bread fortified with flaxseed cake for Tenebrio molitor rearing. RESULTS: Our results showed that fortification seemed to slow the hardening rate of bread, particularly if baker's yeast was used. The time necessary for mold to appear in sourdough bread doubled (from 2 to 4 days). The addition of flaxseed cake to the recipe determined an increase of its scrap consumption by T. molitor larvae. We also observed a significant increase in the body mass of the T. molitor larvae fed with bread obtained with the brewer's yeast with respect to larvae fed with the sourdough. CONCLUSION: Taken together, these preliminary data can indicate that sourdough bread fortified with 5% of flaxseed cake can represent a promising tool to reduce food waste and to recycle bread scraps by a novel zero-waste approach. © 2021 Society of Chemical Industry.

Reconsidering Hydrosols as Main Products of Aromatic Plants Manufactory: The Lavandin (Lavandula intermedia) Case Study in Tuscany.

: The present work evaluates for the first time two Lavandin (Lavandula × intermedia Emeric ex Loisel.) aromatic waters obtained from different plant organs, the flowers and the stems. Both extracts were analysed by GC-MS, which indicates semi-quantitative differences between the major metabolites including linalool, 1,8-cineole, camphor, linalyl acetate and 4-terpineol. 1H-NMR and LC-MS investigation confirmed the presence of these compounds. Moreover, behavioural tests with the food insect pest Tribolium confusum (Coleoptera Tenebrionidae) showed a good repellency for both hydrosols extracts with RD50 values of 3.6 and 3.3 µL cm-2 for the flowers and stems, respectively; at the higher concentrations, however, the hydrosol extract from the flowers is expected to be more effective than the one from the stems. The effect of the flowers and stems aromatic water of Lavandin on seed germination of Raphanus sativus was also evaluated. Results showed that seed germination was completely inhibited by flowers hydrolate, having a possible application as natural herbicide. The overall experience with these Lavandin extracts indicates the potential of improved hydrolates to become the main distillation products, rather than by-products, of the aromatic plants manufacturing; this stimulates further discussions about the potential positive impacts that such a shift could have in the context of ecopharmacognosy.

Leaf and Flower Extracts from the Dwarf Elder (Sambucus ebulus): Toxicity and Repellence against Cosmopolitan Mosquito-Borne Diseases Vectors.

As there has been no scientific evidence of the bioactivity of Sambucus ebulus (Adoxaceae) extracts against insects, we chemically characterized S. ebulus leaves and flowers extracted in methanol and water. The crude extracts, phenolic compounds, and amino acids isolated were tested as larvicides against the fourth-instar larvae of Aedes albopictus and Culex pipiens (Diptera: Culicidae). To understand their mode of action, we evaluated the in vitro acetylcholinesterase (AChE) inhibitor effect of the crude extracts on the two mosquito larvae through a colorimetric method. Furthermore, the deterrent effect of the crude extracts against ovipositing Ae. albopictus females was assessed in the open field. Twelve phenylpropanoids and fourteen amino acids were detected in the extracts, with a prevalence of hydroxycinnamic acids and nonaromatic amino acids. The most toxic compound to Ae. albopictus larvae after 24 h was gallic acid, followed by the crude S. ebulus leaf extract; on Cx. pipiens, it was the crude flower extract. The AChE test showed higher inhibition on both mosquito species exerted by the leaf extract if compared to the flower extract, and it also deterred oviposition by Ae. albopictus females starting from the third day. The results indicated that vegetal extracts could effectively help in the integrated vector management of mosquitoes.

Multiple Functions of Malpighian Tubules in Insects: A Review.

The Malpighian Tubules (MTs) are the main excretory organs in most insects. They play a key role in the production of primary urine and osmoregulation, selectively reabsorbing water, ions, and solutes. Besides these functions conserved in most insects, MTs can serve some specialized tasks at different stages of some species' development. The specialized functions include the synthesis of mucopolysaccharides and proteins for the building of foam nests, mucofibrils for the construction of dwelling tubes, adhesive secretions to help the locomotion, and brochosomes for protection as well as the usage of inorganic salts to harden the puparia, eggs chorion, and pupal cells' closing lids. MTs are also the organs responsible for the astonishing bioluminescence of some Diptera glowworms and can go through some drastic histological changes to produce a silk-like fiber utilized to spin cocoons. The specialized functions are associated with modifications of cells within the entire tubules, in specific segments, or, more rarely, modified secretory cells scattered along the MTs. In this review, we attempted to summarize the observations and experiments made over more than a century concerning the non-excretive functions of insects' MTs, underlying the need for new investigations supported by the current, advanced technologies available to validate outdated theories and clarify some dubious aspects.

Chemical vs. Enzymatic Refining to Produce Peanut Oil for Edible Use or to Obtain a Sustainable and Cost-Effective Protector for Stored Grains against Sitophilus zeamais (Coleoptera: Curculionidae).

Among the various existing techniques, enzymatic degumming represents a process that is establishing itself as a valid alternative to the more classic chemical processes. Moreover, vegetable oils of various origins have been gaining more consideration as sustainable and affordable protectants for cereals and pulses against the attack of several insect pests. Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae) is one of the key pests of cereal crops in the field and in stored and processed cereal products. Based on these highlighted issues, the overall aim of this research was twofold: (i) firstly, the effectiveness of the enzymatic degumming process was evaluated through the use of three different enzymes in order to verify the possible industrial application within the SALOV company as an alternative to the conventional chemical process; (ii) in a second phase, the possible use of the innovative refined oils was explored for sustainable stored grain protection towards S. zeamais. The results obtained confirm the strong possibility of applying the enzymatic process, which is innovative and, in a chemical way, more sustainable than the classical one. Regarding the toxicity towards S. zeamais, the crude peanut oil and the chemically refined peanut oil had lower LC50 values (1.836 and 1.372 g kg-1, respectively) than the oils rectified through enzymatic degumming (LC50 from 2.453 to 4.076 g kg-1), and, therefore, they can be suggested as sustainable stored grain protectants.

Chitosan and Essential Oils Combined for Beef Meat Protection against the Oviposition of Calliphora vomitoria, Water Loss, Lipid Peroxidation, and Colour Changes.

Meat production has a higher economic and ecological impact than other commodities. The reduction in meat loss and waste throughout the whole supply chain is a demanding challenge. In recent years, the interest in the food-grade polysaccharide chitosan (CH) and essential oils (EOs) employed as allies in meat protection has increased. In this work, we selected five EOs obtained from plants traditionally used as spices, and after their chemical characterisation, a trained panel of expert sensorial analysts determined that, among them, Laurus nobilis (Lauraceae) and Piper nigrum (Piperaceae) EOs were the most suitable to season meat. Therefore, the effect of CH, the L. nobilis and P. nigrum EOs, and EOs-enriched CH solutions on meat was tested to assess how they deter the oviposition behaviour of the blowfly Calliphora vomitoria (Diptera: Calliphoridae) and against water loss, lipid peroxidation, and colour changes. All the applied treatments, compared to the control, did not accelerate meat dehydration but increased colour lightness, an attractive feature for consumers, and discouraged the blowfly's oviposition. In particular, the P. nigrum EO-enriched CH was the most active in repelling C. vomitoria without negatively affecting the organoleptic qualities and shelf-life of meat.

Bioactivity of Different Chemotypes of Oregano Essential Oil against the Blowfly Calliphora vomitoria Vector of Foodborne Pathogens.

Blowflies play a substantial role as vectors of microorganisms, including human pathogens. The control of these insect pests is an important aspect of the prevention of foodborne diseases, which represent a significant public health threat worldwide. Among aromatic plants, spices essential oils (EOs) are the most suitable to protect food from insect pests. In this study, we determined the chemical composition of three oregano EOs and assessed their toxicity and deterrence to oviposition against the blowfly Calliphora vomitoria L. The chemical analyses showed that the EOs belonged to three chemotypes: one with a prevalence of carvacrol, the carvacrol chemotype (CC; carvacrol, 81.5%), and two with a prevalence of thymol, the thymol/p-cymene and thymol/γ-terpinene chemotypes (TCC and TTC; thymol, 43.8, and 36.7%, respectively). The bioassays showed that although all the three EOs chemotypes are able to exert a toxic activity against C. vomitoria adults (LD50 from 0.14 to 0.31 µL insect-1) and eggs (LC50 from 0.008 to 0.038 µL cm-2) as well as deter the oviposition (Oviposition Activity Index, OAI, from 0.40 ± 0.04 to 0.87 ± 0.02), the bioactivity of oregano EOs significantly varies among the chemotypes, with the thymol-rich EOs (TCC and TTC) overall demonstrating more effectiveness than the carvacrol-rich (CC) EO.

Andean Plants Essential Oils: A Scented Alternative to Synthetic Insecticides for the Control of Blowflies.

Blowflies are vectors of microorganisms and human pathogens, and their maggots cause myiasis in vertebrates and infest and spoil meat and fish products. Essential oils (EOs) from spices were proven to be a safer and more sustainable alternative to synthetic insecticides for the control of blowflies and are suitable for protecting food from such pests. However, some EOs are not acceptable for environmental or topical applications due to their strong, unpleasant odour. In this study, we measured the acute toxicity and the repellence of two EOs extracted from the Andean plants Aloysia citrodora Palau and Bursera graveolens (Kunth) Triana and Planch., both known for their pleasant odour, against the blue blowfly Calliphora vomitoria (L.) (Diptera: Calliphoridae). We also compared their bioactivity with that of the Allium sativum L. EO, which is very effective but bad-smelling. The A. citrodora EO was mainly rich in oxygenated monoterpenes, the most abundant of which were geranial (26.8%) and neral (21.0%). The B. graveolens EO was chiefly composed of monoterpene hydrocarbons, mostly represented by limonene (46.2%). According to the sensory description, the best odour profile was associated with the A. citrodora EO, while the olfactory expression of the EO from B. graveolens was negatively affected by a strong odour of "mouldy lemon". The behavioural test showed that the A. citrodora EO was more repellent than that of A. sativum and, on the contrary, that the B. graveolens EO was attractive. The toxicity tests showed that the EOs of both Andean plants have a clear toxic effect on the C. vomitoria eggs and adults. In terms of ovicidal activity, there were no significant differences among the effects of the three tested EOs. On the adult flies, the toxicity of the two EOs of the Andean plants was much lower than that of A. sativum (LC50 fumigation = 1.86 µL EO L-1 air; LC50 ingestion = 8.10 µL EO mL-1 gel) both by fumigation (LC50 = 23.66 and 25.30 µL EO L-1 air for A. citrodora and B. graveolens, respectively) and ingestion (LC50 = 36.65 and 44.97 µL EO mL-1 gel for A. citrodora and B. graveolens, respectively), while, by contact, the A. citrodora EO (LD50 = 0.27 µL EO insect-1) was more toxic than the A. sativum EO (LD50 = 0.46 µL EO insect-1).

Biological Notes and Distribution in Southern Europe of Aclees taiwanensis Kȏno, 1933 (Coleoptera: Curculionidae): A New Pest of the Fig Tree.

Ficus carica L. is one of the earliest cultivated fruit trees, and figs are a typical fruit of the Mediterranean diet and traditional medicine as well. In recent years, a new pest, the black weevil Aclees taiwanensis Kȏno, 1933 (Coleoptera: Curculionidae) native to Asia, has been recorded in France and Italy. Aclees taiwanensis causes the rapid death of the fig tree by its larvae that dig alimentation galleries in the trunk and surface roots, compromising the phloem flux. In Italy, from 2005, the year of the first detection of A. taiwanensis, the fig production has nearly halved, decreasing from 20.09 t to 10.65 t. To date, no specific EU regulation has been applied to prevent the A. taiwanensis spread, and we can reasonably expect a rapid diffusion of this pest all over the Mediterranean area. To avoid the loss of the Mediterranean fig orchards, effective strategies to detect and control the black weevil are required. Such strategies need a detailed knowledge of A. taiwanensis distribution, biology, and physiology. This paper updates the known distribution of this species in Southern Europe, using a citizen science approach, and describes, under laboratory and field conditions, its main biological traits.

Andean Flora as a Source of New Repellents against Insect Pests: Behavioral, Morphological and Electrophysiological Studies on Sitophilus zeamais (Coleoptera: Curculionidae).

Sitophilus zeamais (Motschulsky) is considered as one of the most destructive foodstuff pests. Due to their efficiency, low toxicity for mammalians and low environmental impact, plant-derived essential oils (EOs) are promising tools for pest control. In particular, the OEs extracted from Lamiaceae are considered among the most bioactive in terms of repellent and/or insecticidal effect. Here, we investigated the repellence of the EOs extracted from two aromatic plant species typical of the flora of the Ecuadorian Andes, Clinopodium tomentosum and C. nubigeum, against adults of S. zeamais. The behavioral assays carried out at concentrations ranging from 0.7 to 23.9 µL L-1 air in a two-way static olfactometer showed a significant repellent effect starting from the concentration of 8.4 mL L-1 air both for the EO of C. nubigenum and C. tomentosum. We also carried out a complete structural analysis of the antenna of S. zeamais using scanning (SEM) and transmission electron microscopy (TEM), in order to characterize the olfactory sensilla equipment. In this species, there is no sexual dimorphism also as regards to the antennal morphology and the sensilla type and distribution. We identified six type of sensilla, among which at least three types (Sensillum Trichoideum 1, Sensillum Trichoideum 2 and Grooved Peg Sensillum) can be considered as olfactory. Electroantennography (EAG) recordings carried out on S. zeamais revealed a positive dose-response to both EOs, without differences between the two sexes.