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The purpose of this research is to identify and investigate some natural dyes with halochromic properties for potential use as food spoilage indicators to reduce waste and curve the negative effects of food borne diseases.

Exactly 10 potential dye-yielding plants were selected based on their colour (mostly purple, red, maroon and pink). Solvent extraction was used to extract the dyes and pH differential method was used to determine the concentrations of anthocyanin in the extracted dyes. Different concentrations of hydrochloric acid and sodium hydroxide (0.1 M, 1 M and 2 M) in drops and in excess as acidic and basic solution, respectively, were used to test the halochromicity of the extracted dyes. Methyl red (a synthetic dye) was used as a reference standard/control. The pH of the dyes was recorded before and after addition of both NaOH and HCl solutions.

Five out of the 10 dyes extracted (labelled as dye A–E for Ti plant (green Cordyline fruticosa), coleus (Coleus blumei), paper flower (Bougainvillea glabra), painted nettle (Palisandra coleus) and purple heart (Setcresea purpurea), respectively, were found to be halochromic (even at low doses) by changing its colour when exposed to both acidic and basic solutions. While other dyes labelled F–J for red acalypha (Acalypha wilkesiana), golden shower (Cassia fistula), golden dew drop (Duranta repens), wild sage (Lantana camara var Aculeata) and pink oleander (Apocynaceae Nerium oleander), respectively, were either completely insensitive to the solutions in drops, slightly sensitive at high doses or the colour change is insignificant. Although some dyes were found to be more sensitive than others but in most cases, the colour changes in halochromic dyes were more stable in acidic conditions than in basic making it more sensitive to the basic than the acidic solution with the exception of dye A and E (to some extent) which was sensitive to both acidic and basic solution. The anthocyanin contents of dye A–J were found to be between the range of 2.28–10.35 mg/l with dye E having the lowest and dye J with the highest anthocyanin concentration, respectively. The initial pH of all the dyes falls within the range of 4.8–7.3 with most found within the acidic range.

Halochromic dye research studies are still at the infancy stage in developing world despite the vast available and abundant potential natural halochromic dye-yielding plants. The study explored this area of research and gives an opportunity for the development of smart packaging for pH-sensitive foods using natural dyes as an alternative to conventional synthetic dyes to reduce cost and also curve the negative effect of synthetic dyes as well as food borne diseases.

The purpose of this paper is to provide insight into the consumers’ perception of natural and artificial food colourants. Furthermore, attitudes towards the application of carmine, being technically important and ubiquitously used to impart red shades, are assessed and analysed. Originating from insects, carmine is considered as natural but may arouse disgust.

In total, 625 individuals were surveyed using an online, self-administered questionnaire to represent a broad cross-section of the German population.

Independent of their origin, the application of colourants was rejected by 57.0 per cent of the interviewees. In total, 31.8 per cent of the participants stated a neutral attitude, while only 11.2 per cent expressed a positive notion. Most respondents preferred colourants from natural sources to artificial ones. While consumers perceive natural food colourants composed of genuine plant pigments positively, 61.6 per cent of respondents disliked the application of animal-derived colourants, 24.8 per cent of them did neither reject nor like it, and only 13.6 per cent of the interviewees stated a positive attitude towards them. The findings of this paper further indicate consumers’ preference for colourants to be either artificial or plant-derived rather than carmine. Food colourants are being rejected, possibly due to misleading information and confusing labelling. Consequently, information about carmine, including its origin and production, did not increase the aversion to products that are dyed with it, but increased their acceptance.

This study outlines consumer perception and attitudes towards food colourants. For the first time, the findings of this paper report the effect of revealing information about an additive, which initially aroused disgust, and its influence on consumer perception.

Fruits and vegetables, being good source of energy, health promoting and protecting compounds with unique taste and flavor, are attracting consumers since ages. These horticultural produces start deterioration just after harvest; therefore, their proper storage is must during transportation and storage to retain maximum quality parameters and for good market value. Best storage conditions are required to prevent growth of micro flora and to maintain the nutritional values of harvested produce. Retailers and processors in every corner of world want to move toward the cheaper ways to increase the shelf life and texture of horticultural crops for better consumer preference. The purpose of this paper is to make consumers and researchers aware about different post harvest malpractices in fresh fruits and vegetables.

Lot of chemicals like colors, artificial ripening agents, sweeteners and waxes are applied on surface of horticulture produce to siphon off money from consumers, and these have adverse health effects directly or indirectly. Various regulatory agencies have launched various programs, acts and laws for monitoring and avoiding such unhealthy ways. Regulatory bodies launched training programs also for the food handlers and consumers to ensure the food safety from farm to fork.

This paper will throw light on different malpractices followed by retailers to manipulate the quality which causes adverse health effects and to create consumer awareness regarding such malpractices.

The paper emphasizes on current malpractices followed by retailers to mislead the consumers about fruits’ and vegetable’ quality by using sweeteners, colors and other chemical. On prolonged consumption, such substances lead to major health issues such as attention disorder.

Reports of a number of countries imposing a limited ban on the use of D.D.T. have appeared from time to time in the B.F.J., but in the last few months, what was a trickle seems to have become an avalanche. In Canada, for example, relatively extensive restrictions apply from January 1st, permitting D.D.T. for insect control in only 12 agricultural crops, compared with 62 previously; there is a reduction of maximum levels for most fruits to 1 ppm. Its cumulative properties in fat are recognized and the present levels of 7 ppm in fat of cattle, sheep and pigs are to remain, but no trace is permitted in milk, butter, cheese, eggs, ice cream, other dairy products, nor potatoes. A U.S. Commission has advised that D.D.T. should be gradually phased out and completely banned in two years' time, followed by the Report of the Advisory Committee on Pesticides and Other Toxic Chemicals recommending withdrawal in Britain of some of the present uses of D.D.T. (also aldrin and dieldrin) on farm crops when an alternative becomes available. Further recommendations include an end to D.D.T. in paints, lacquers, oil‐based sprays and in dry cleaning; and the banning of small retail packs of D.D.T. and dieldrin for home use in connection with moth‐proofing or other insect control. The Report states that “domestic users are often unaware that using such packs involve the risk of contaminating prepared food immediately before it is eaten”.

A graft copolymer (PBW-g-PAM) of Moringa seed was prepared. The phosphate buffer washed seed powder and polyacrylamide were reacted, using ceric ion initiator. The grafted copolymer was tested for its efficiency for metal removal (Cr-VI) from tannery effluent and for color removal from textile effluent using standard spectroscopic methods. The paper aims to discuss these issues.

The PBW-g-PAM was prepared by standard method and characterized by FT-IR, SEM, UV-vis, XRD and DSC/TGA analyses.

The effects of PBW-g-PAM dose, contact time and pH on percent removal of Cr-VI and dye color, have been reported.

The efficiency of metal removal was shown to be 99 per cent in just 15 min. Similar results were obtained for efficient color removal from textile effluents. It is for the first time that graft polymer of Moringa seed has been used for metal and color removal.

The paper aims to analyse the effect of acid hydrolysis on the chemical composition and the biological activities of Rubia tinctorum collected from the south of Tunisia. It proposes to clarify the relationship between alizarin content and the antioxidant and antimicrobial activities of Rubia extract.

The paper opted for analytical tools (HPLC) and the in-vitro study of biological activities, namely, the antioxidant activity which is evaluated using the radical scavenging assay (ABTS) and ferric reducing power assay (FRAP); the antimicrobial activity is tested using the wells agar diffusion method.

The paper provides information about the positive effect of acid hydrolysis, namely, the enhancement of alizarin content in the extract which has increased its antioxidant and antimicrobial activities.

This paper fulfils an identified need to study the relationship between the chemical composition, biological activities and colour enhancement.

Whey is a by-product of paneer, cheese and casein industry and considered as a dairy waste. Worldwide, approximately 180–1,900 million tons of whey is produced annually. Whey is classified as a high pollutant due to its organic matter level. Owing to its high chemical oxygen demand and biological oxygen demand, it is a big threat to the environment. Whey contains 4.5%–5.0% lactose, 0.6%–0.7% protein, 0.4%–0.5% lipids, vitamins and minerals. Due to its high nutritional profile, it is a good substrate for the microorganisms for production of natural pigments. The purpose of this paper is to review the utilization of low cost substrate (whey) for production of various types of pigments and their applications in different sectors.

The databases for the search included: Scopus, PubMed, Science Direct, Web of Science, Research gate and Google. The main search was directed towards different types of natural pigments, stability, technologies for enhancing their production and contribution towards circular economy. Approximately 100 research papers were initially screened. A global search was conducted about natural pigments. Research articles, review papers, books, articles in press and book chapters were the type of search for writing this review paper.

Production of natural pigments using whey and their addition in food products not only improves the colour of food but also enhances the antioxidant properties of food products, helping the health benefits by chelating free radicals from the body. The sustainable use of whey for production of natural pigments can improve the bio-based economy of different industries and thereof the national economy.

Efficient utilization of whey can bring a lot more opportunities for production of natural pigments in a sustainable manner. The sustainable approach and circular economy concepts will benefit the dependent industries and health conscious consumers. The potential uses of whey for the production of natural pigments using diverse organisms are highlighted in this paper.

The purpose of this paper is to present the latest subscale demonstrator aircraft developed at Linköping University. It has been built as part of a study initiated by the Swedish Material Board (FMV) on a Generic Future Fighter aircraft. The paper will cover different aspects of the performed work: from paper study realised by SAAB to the first flight of the scaled demonstrator. The intention of the paper is to describe what has been realised and explain how the work is may be used to fit within aircraft conceptual design.

The approach has been to address the challenges proposed by the customer of the demonstrator, how to design, manufacture and operate a scaled demonstrator of an aircraft study in conceptual design within five months. Similar research projects have been reviewed in order to perform the current work.

The results obtained so far have led to new questions. In particular, the project indicated that more research is needed within the area of subscale flight testing for usage in aircraft conceptual design, since a scaled demonstrator is likely to answer some questions but will probably open up new ones.

The current research is just in its infancy and does not bring any final conclusion but does, however, offer several guidelines for future works. Since the aircraft study was an early phase concept study, not much data are available for validation or comparison. Therefore, the paper is not presenting new methods or general conclusions.

Results from a conceptual aircraft study and a realisation of a scaled prototype are presented, which show that scaled flight testing may be used with some restriction in conceptual design.

The value of this paper is to show that universities can be involved in prototype development and can work in close collaboration with industries to address issues and solutions within aircraft conceptual design.

This paper aims to study the color change kinetics of lac dye in response to pH and food spoilage metabolites (ammonia, lactic acid and tyramine) for its potential application in intelligent food packaging.

UV-Vis spectroscopy was used to study the color change of dye solution. Ratio of absorbance of dye solution at 528 nm (peak of ionized form) to absorbance at 488 nm (peak of unionized form) was used to study the color change. Color change kinetics was studied in terms of change in absorbance ratio (A528/A488) with time using zero- and first-order reaction kinetics. An indicator was prepared by incorporating lac dye in agarose membrane to validate the result of study for monitoring quality of raw milk.

Dye was orange-red in acidic medium (pH: 2 to 5) and exhibited absorbance peak at 488 nm. It turned purple in alkaline medium (pH: 7 to10) and exhibited absorbance peak at 528 nm. The change in absorbance ratio with pH followed zero-order model. Acid dissociation constant (pKa) of dye was found to be 6.3. Color change of dye in response to ammonia and tyramine followed zero-order reaction kinetics, whereas for lactic acid, the first-order model was found best. In the validation part, the color of the indicator label changed from purple to orange-red when the milk gets spoiled.

The study opens a new application area for lac dye. The results suggest that lac dye has potential to be used as an indicator in intelligent food packaging for detection of spoilage in seafood, meat, poultry and milk.

The purpose of this paper was to study the color change kinetics of lac dye in response to aldehydes, carbon dioxide and other food spoilage metabolites for its potential application in intelligent food packaging.

UV–Vis spectroscopy was used to study the color change of dye solution. Ratio of absorbance of dye solution at 528 nm (peak of ionized form) to absorbance at 488 nm (peak of unionized form) was used to study the color change. Color change kinetics was studied in terms of change in absorbance ratio (A₅₂₈/A₄₈₈) with time using zero and first-order reaction kinetics. Lac dye-based indicator was prepared to validate the result of study for monitoring quality of strawberries.

Lac dye was orange-red in acidic medium and purple in alkaline medium. Color change of dye in response to benzaldehyde followed zero-order reaction kinetics, whereas for carbon dioxide first-order model was found best. No color change of dye solution was observed for alcohols, ketones and sulfur compounds. In the validation part, the color of the indicator label changed from purple to orange when the strawberries spoiled.

The study expands application area for lac dye as sensing reagent in intelligent food packaging for spoilage or ripeness detection of fruits and vegetables.