Feasibility of Using a Cheap Colour Sensor to Detect Blends of Vegetable Oils in Avocado Oil.

This proof-of-concept study explored the use of an RGB colour sensor to identify different blends of vegetable oils in avocado oil. The main aim of this work was to distinguish avocado oil from its blends with canola, sunflower, corn, olive, and soybean oils. The study involved RGB measurements conducted using two different light sources: UV (395 nm) and white light. Classification methods, such as Linear Discriminant Analysis (LDA) and Least Squares Support Vector Machine (LS-SVM), were employed for detecting the blends. The LS-SVM model exhibited superior classification performance under white light, with an accuracy exceeding 90%, thus demonstrating a robust prediction capability without evidence of random adjustments. A quantitative approach was followed as well, employing Multiple Linear Regression (MLR) and LS-SVM, for the quantification of each vegetable oil in the blends. The LS-SVM model consistently achieved good performance (R2 > 0.9) in all examined cases, both for internal and external validation. Additionally, under white light, LS-SVM models yielded root mean square errors (RMSE) between 1.17-3.07%, indicating a high accuracy in blend prediction. The method proved to be rapid and cost-effective, without the necessity of any sample pretreatment. These findings highlight the feasibility of a cost-effective colour sensor in identifying avocado oil blended with other oils, such as canola, sunflower, corn, olive, and soybean oils, suggesting its potential as a low-cost and efficient alternative for on-site oil analysis.

Membrane Cascade Fractionation of Tomato Leaf Extracts-Towards Bio-Based Crop Protection.

Promising initial results from the use of membrane-fractionated extracts of tomato leaf as crop protection agents have recently been reported. This paper provides additional evidence from larger scale experiments that identify an efficient pipeline for the separation of tomato leaf extracts to generate a fraction with significant defence elicitor activity. A UF tubular membrane 150 kDa, with an internal diameter of 5 mm, proved appropriate for initial extract clarification, whereas afterwards a UF 10 kDa and three NF membranes (200-800 Da) in sequence were evaluated for the subsequent fractionation of this tomato extract. The compositions of sugars, proteins and total biophenols were changed in these fractions with respect to the initial extract. The initial extract ratio of sugars: proteins: biophenols was 1:0.047:0.052, whereas for the retentate of the 800 Da NF membrane, which has the higher crop protection activity, this ratio was 1:0.06:0.1. In this regard, it appears that the main crop protection effect in this fraction was due to the sugars isolated. It was found that with the appropriate membrane cascade selection (UF 150 kDa, UF 10 kDa and NF 800 Da) it was possible to produce (easily and without the need of additional chemicals) a fraction that has significant activity as an elicitor of disease resistance in tomato, whereas the remaining fractions could be used for other purposes in a biorefinery. This is very promising for the wider application of the proposed approach for the relatively easy formulation of bio-based aqueous streams with bio-pesticide activities.

Escherichia coli as an antibody expression host for the production of diagnostic proteins: significance and expression.

This review article concerns the production of recombinant antibody fragments for applications mainly in the diagnostic sector. The so-called "point of care diagnostics" is very important for timely diagnosis and treatment, thus being able to save lives and resources. There is intense pressure for more accurate and less expensive rapid diagnostic tests, with a value preferably <$1. Thus, the large-scale cost-effective production of recombinant antibodies is vital. The importance of Escherichia coli toward the production of inexpensive rapid tests will be explained in this review paper. Details about the different strains of E. coli, the strategies used for the insertion and the expression of recombinant proteins, and the challenges that still exist are provided. Afterward, the importance of the expression scale and culture parameters in the final yield of the antibodies are examined. From this analysis, it appears that for good yields of recombinant antibodies, aside from appropriate gene transfer and expression, the culturing parameters are of paramount importance. Larger scale production is more favorable, mainly due to the higher cell densities that can be achieved. Yields of functional Fab fragments in the range of 10-20 mg/L are considered good in shake flasks, whereas in bioreactors can be up to 1-2 g/L. An amount of 10-500 mg of such antibody per million rapid tests is required. Despite the substantial importance of the production of the antibodies and their fragments, their downstream processing should be appropriately considered from the beginning for achieving the target value of the final rapid diagnostic tests.

Natural Origin Lycopene and Its "Green" Downstream Processing.

Lycopene is an abundant natural carotenoid pigment with several biological functions (well-known for its antioxidant properties) which is under intensive investigation in recent years. Lycopene chemistry, its natural distribution, bioavailability, biological significance, and toxicological effects are briefly outlined in the first part of this review. The second, major part, deals with various modern downstream processing techniques, which are assessed in order to identify promising approaches for the recovery of lycopene and of similar lipophilic compounds. Natural lycopene is synthesized in plants and by microorganisms, with main representatives of these two categories (for industrial production) tomato and its by-products and the fungus Blakeslea trispora, respectively. Currently, there is a great deal of effort to develop efficient downstream processing for large scale production of natural-origin lycopene, with trends strongly indicating the necessity for "green" and mild extraction conditions. In this review, emphasis is placed on final product safety and ecofriendly processing, which are expected to totally dominate in the field of natural-origin lycopene extraction and purification.

Lycopene recovery from tomato peel under mild conditions assisted by enzymatic pre-treatment and non-ionic surfactants.

The tomato processing industry generates large quantities of tomato peel residues, usually creating environmental problems. These residues are a significant source of lycopene, thus providing an attractive alternative for profitable handling of these otherwise problematic by-products. The enzymatic pretreatment of these residues for lycopene recovery has already been employed, although the use of surfactants for enhancing the recovery has not been examined so far. The enzymatic pretreatment of tomato peels, using two commercially available pectinolytic enzyme preparations, was evaluated suggesting that there is an optimum pretreatment time of about 1 h, enzyme amount 250 Units/mL and no significant pH influence. Lycopene surfactant - assisted extraction was further investigated, showing that, among eight surfactants used, the most suitable was "Span 20", with an optimum ratio of 6-7 surfactant molecules per lycopene molecule. Sequential enzymatic pretreatment and surfactant-assisted extraction (30 min for each step) was evaluated leading to an improved lycopene extraction yield, with a somewhat smaller surfactant molar ratio (i.e. 4-5). In the latter case, the yield of lycopene recovery was almost four times greater compared to just 1 hr enzymatic pretreatment, and was approximately ten times greater compared to the recovery from untreated peels. Furthermore, such lipophilic compound recovery, avoiding the use of organic solvents, is environmentally attractive and ensures direct lycopene use in the food and cosmetics industries.

Agro-food wastes utilization by Blakeslea trispora for carotenoids production.

The all-trans-ß-carotene is a natural pigment used in various industrial fields (food, cosmetics, pharmaceuticals, etc) and possesses the higher provitamin A activity, in respect to other carotenoids. All-trans-ß-carotene is produced industrially by chemical and biotechnological means. For ß-carotene biotechnological production in industrial scale mated cultures of Blakeslea trispora, a heterothallic fungus, are mainly used. Despite the intense research for ß-carotene production by B. trispora, natural substrate utilization has not been extensively studied. Solid agro-food wastes such as cabbage, watermelon husk and peach peels from northern Greece as main carbon source into submerged B. trispora cultures for carotenoids production, was examined. The media containing only the agro-food waste (2-4) gave a biomass accumulation 7.77 ± 0.4 g/L, while a reference medium 1 with glucose (10 g/L) gave 4.65 ± 0.21 g/L. In another experiments series agro-food wastes were used with corn steep liquor and thiamine (media 6-8), giving a biomass accumulation and total carotenoid volumetric production 10.2 ± 2.41 g/L and 230.49 ± 22.97 mg/L, respectively. These are the higher values reported for solid wastes so far in respect to those obtained from a synthetic medium, with higher glucose concentration of 50 g/L where the correspondent values were 9.41 ± 1.18 g/L and 45.63 mg/L respectively. The results support that B. trispora is able to utilize, almost equivalently, different origin agro-food wastes for carotenoids production. Furthermore, ß-carotene percentage in all examined cases was over 76%, as it was estimated by HPLC analysis, suggesting that these agro food wastes may be used for high purity, large scale ß carotene production.

Raman spectroscopy for intracellular monitoring of carotenoid in Blakeslea trispora.

In the present study, we explore the feasibility of Raman spectroscopy for intracellular monitoring of carotenoid in filamentous fungi Blakeslea trispora. Although carotenoid production from this fungus has been extensively studied through various chromatographic methods and ultraviolet-visible spectroscopy, no intracellular monitoring has been demonstrated until now. The intensity of the Raman spectrum, and more conveniently that of the strongest nu(1) carotenoid band at approximately 1,519 cm(-1), exhibits a good linear correlation with the carotenoid content of the sample as determined by high-performance liquid chromatography (HPLC) and ultraviolet-visible (UV-Vis) spectroscopy. Our results suggest that Raman spectroscopy can serve as an alternative method for the study and quantification of carotenoid in batch-mated submerged cultivations of B. trispora and similar organisms. Although not as accurate as HPLC, it allows a rapid sampling and analysis, avoiding the prolonged and tedious classical isolation procedures required for carotenoid determination by HPLC and UV-Vis spectroscopy.