Jaime López-Cervantes

HPLC method validation for measurement of sulforaphane level in broccoli by-products

A simple and specific analytical method was developed and tested for the determination of sulforaphane in broccoli by-products. The method includes the optimization of the conversion of glucoraphanin to sulforaphane, followed by purification of extracts using solid-phase extraction and high-performance liquid chromatography (HPLC) analysis. The response surface methodology was used to find optimum conditions for the preparation and purification procedure. Chromatographic conditions for reversed-phase HPLC with UV photodiode array detection were as follows: column, Exil ODS C(18), 25 x 0.46 cm, 5 microm; column temperature, 36 degrees C; mobile phase, a 30 : 70 (v/v) mixture of acetonitrile:water; flow rate, 0.6 mL/min. The detection wavelength was UV 202 nm. Under these conditions, excellent linearity was obtained (r(2) = 1), and the overall recovery was 97.5 and 98.1% for fresh florets and lyophilized florets, respectively. The precision results showed that the relative standard deviation of the repeatability for florets fresh and lyophilized was 3.0 and 4.0%, respectively. Sulforaphane contents were determined in the edible portion of fresh broccoli, and broccoli crop remains.

Preparation and characterization of durum wheat (Triticum durum) straw cellulose nanofibers by electrospinning.

Cellulose nanofibers from durum wheat straw ( Triticum durum ) were produced and characterized to study their potential as reinforcement fibers in biocomposites. Cellulose was isolated from wheat straw by chemical treatment. Nanofibers were produced via an electrospinning method using trifluoroacetic acid (TFA) as the solvent. The nanofibers were 270 ± 97 nm in diameter. Analysis of the FT-IR spectra demonstrated that the chemical treatment of the wheat straw removed hemicellulose and lignin. XRD revealed that the crystallinity of the cellulose was reduced after electrospinning, but nanofibers remained highly crystalline. The glass transition temperature (T(g) value) of the fibers was 130 °C, higher than that of cellulose (122 °C), and the degradation temperature of the fibers was 236 °C. Residual TFA was not present in the nanofibers as assessed by the FT-IR technique.

Biochemical composition and physicochemical properties of broccoli flours

The objective of this research was to study the biochemical composition and physicochemical properties of three different flours prepared from broccoli crop remains. Florets, leaves and stalks of broccoli were dried at 60°C, and the flours obtained were analysed for proximate composition, amino acid profile, fatty acid composition, and physicochemical properties. The florets flour showed the highest protein content (22.41 g/100 g dry weight); ash was higher in leaves flour (14.67 g/100 g dry weight), and the lipid content was similar in the flours of leaves and stalks. The stalks flour had high crude fibre content and low protein content. All flours presented a high water absorption index. Tyrosine, aspartic acid, glutamic acid, proline and valine were found in larger concentration. The most abundant fatty acids in the lipids were linolenic acid (C18:3n3), palmitic acid (C16:0) and linoleic acid (C18:2n6). Broccoli flours prepared in this study are good source of nutrients and could be utilized as dietary supplements.

Physicochemical, Nutritional and Antioxidant Properties of Tempeh Flour from Common Bean (Phaseolus vulgaris L.)

The effects of solid state fermentation (SSF) on physicochemical, nutritional and antioxidant properties of common bean flour were studied. SSF increased protein content (21.7%) and decreased lipids (-38.4%), carbohydrates (-3.5%) and phytic acid (-58.3%). Fermented (tempeh) flour showed higher dispersability, lower water solubility index and pH than unfermented flour. Fermentation also increased an average of 0.21 g/100 g protein, six of the essential amino acids (EAAs), including total sulfur (Met + Cys), the limiting EAAs in unfermented flour (score = 0.91); Lys and Trp decreased 0.21 and 0.09 g/100 g protein, respectively. SSF improved the in vitro protein digestibility and the calculated protein efficiency ratio. Tempeh flour had 2.2-fold more phenolics than the bean flour and exhibited antiradical activity (43%) and antioxidant activity (38%) correlated with total phenolics content. Common bean tempeh flour may be considered for the fortification of widely consumed legume-based food products and also for the prevention of pathologies associated with oxidative stress.

Effect of the refining process on Moringa oleifera seed oil quality

We evaluated the physicochemical properties and oxidative stability of the oil extracted from the seeds of Moringa oleifera during its refining process. Refining is accomplished in three stages: neutralization, degumming, and bleaching. Four samples were analyzed, corresponding to each step of the processed and crude oil. Increases in the density, viscosity, saponification value and oxidation of the oil were detected during the refining, while the peroxide value and carotenoid content diminished. Moreover, the refractive index and iodine content were stable throughout the refining. Nine fatty acids were detected in all four samples, and there were no significant differences in their composition. Oleic acid was found in the largest amount, followed by palmitic acid and behenic acid. The crude, neutralized, and degummed oils showed high primary oxidation stability, while the bleached oil had a low incidence of secondary oxidation.

Microencapsulation of sulforaphane from broccoli seed extracts by gelatin/gum arabic and gelatin/pectin complexes

Sulforaphane is a phytochemical that has received attention in recent years due to its chemopreventive properties. However, the uses and applications of this compound are very limited, because is an unstable molecule that is degraded mainly by changes in temperature and pH. In this research, the use of food grade polymers for microencapsulation of sulforaphane was studied by a complex coacervation method using the interaction of oppositely charged polymers as gelatin/gum arabic and gelatin/pectin. The polymers used were previously characterized in moisture content, ash and nitrogen. The encapsulation yield was over 80%. The gelatin/pectin complex had highest encapsulation efficiency with 17.91%. The presence of sulforaphane in the complexes was confirmed by FTIR and UV/visible spectroscopy. The materials used in this work could be a new and attractive option for the protection of sulforaphane.

Carotenoids extraction and quantification: a review

In recent years carotenoids have represented a good alternative for the pharmaceutical and food industries and especially for the human health, they prevent different diseases, such cancer, macular degradation and cataracts. The use of post-harvest residues represents a good alternative for obtaining analytes of interest. The application of enzymatic pretreatment over plant matrices has resulted in an increase in the level of extraction and lowered operating costs. Today, the use of organic solvents such as hexane in this process is frequent, however, new investigations with novel environmentally friendly solvents (non-toxic) promise new cleaner technologies. The aim of this review is to present some methodologies and technologies used today to obtain carotenoids from plant residues, industrial and post-harvest materials.

Effect of solvents and methods of stirring in extraction of lycopene, oleoresin and fatty acids from over-ripe tomato

Abstract Lycopene and oleoresin extraction from powder of tomato over-ripe by three agitation methods and four solvents have been evaluated. Also, tomato powder and the oleoresins were characterized biochemically. On average, the moisture content of powder was found to be 4.30, ash 8.90, proteins 11.23 and lipids 4.35 g 100 g−1. The best oleoresin extraction yield was achieved by combining sonication and acetone at 1.43 g 100 g−1. The greatest amount of lycopene (65.57 ± 0.33 mg 100 g−1) was also obtained using the same treatment. The presence of trans-lycopene was positively confirmed by HPLC and FTIR. In oleoresins, linoleic acid (C18:2n6) was the predominant with 50% of total fatty acids, whereas stearic acid (C18:0) is presented in a smaller proportion (5%). A simple and suitable method for extraction of lycopene from over-ripe tomato was optimized. In industrial applications, tomato by-products are a viable source of analytes, such as lycopene and unsaturated fatty acids.

Effect of extrusion processing parameters on anthocyanin content and physicochemical properties of nixtamalized blue corn expanded extrudates

Nixtamalized blue corn expanded extrudates were elaborated in a single screw extruder using feed moisture (FM) of 14, 15, 16, 16.5, 18.5 and 20.5%; ground corn with different particle size indexes (PSI, 83.97 and 94.15), and at a final extruder temperature of 130 and 140°C. The physicochemical properties of extrudates evaluated were moisture content, total anthocyanin and cyanidin 3-glucoside (C3G) content, color, density and expansion index. Extrudates processed at 16 and 16.5% of FM showed higher total anthocyanin and C3G contents. The extrudates processed with 16% FM, at 130°C and PSI of 83.97, showed the highest total anthocyanin content (211.1 mg · kg−1). Cyanidin 3-glucoside showed an increase (11.3%) in extrudates when compared with raw corn. The expansion index was higher for those made with FMs of 14, 15, 16 and 16.5%. The total anthocyanin and C3G contents were not correlated with any other parameter.

Ultra-high pressure LC for astaxanthin determination in shrimp by-products and active food packaging

Nowadays, there is increasing interest in natural antioxidants from food by-products. Astaxanthin is a potent antioxidant and one of the major carotenoids in crustaceans and salmonids. An ultra-high pressure liquid chromatographic method was developed and validated for the determination of astaxanthin in shrimp by-products, and its migration from new packaging materials to food simulants was also studied. The method uses an UPLC® BEH guard-column (2.1 × 5 mm, 1.7 µm particle size) and an UPLC® BEH analytical column (2.1 × 50 mm, 1.7 µm particle size). Chromatographic separation was achieved using a programmed gradient mobile phase consisting of (A) acetonitrile-methanol (containing 0.05 m ammonium acetate)-dichloromethane (75:20:5, v/v/v) and (B) ultrapure water. This method was evaluated with respect to validation parameters such as linearity, precision, limit of detection, limit of quantification and recovery. Low-density polyethylene films were prepared with different amounts of the lipid fraction of fermented shrimp waste by extrusion, and migration was evaluated into food simulants (isooctane and ethanol 95%, v/v). Migration was not detected under the tested conditions.