Unravelling the secret of seedbased gels in water: the nanoscale 3D network formation

Chia (Salvia hispanica) and basil (Ocimum basilicum) seeds have the intrinsic ability to form a hydrogel concomitant with moisture-retention, slow releasing capability and proposed health benefits such as curbing diabetes and obesity by delaying digestion process. However, the underlying mode of gelation at nanoscopic level is not clearly explained or explored. The present study elucidates and corroborates the hypothesis that the gelling behavior of such seeds is due to their nanoscale 3D-network formation. The preliminary study revealed the influence of several conditions like polarity, pH and hydrophilicity/ hydrophobicity on fiber extrusion from the seeds which leads to gelation. Optical microscopic analysis clearly demonstrated bundles of fibers emanating from the seed coat while in contact with water, and live growth of fibers to form 3D network. Scanning electron microscope (SEM) and transmission electron microscope (TEM) studies confirmed 3D network formation with fiber diameters ranging from 20 to 50 nm

Hyperspectral imaging as an effective tool for prediction the moisture content and textural characteristics of roasted pistachio kernels

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. The objective of this study was to develop calibration models for prediction of moisture content and textural characteristics (fracture force, hardness, apparent modulus of elasticity and compressive energy) of pistachio kernels roasted in different conditions (temperatures 90, 120 and 150 °C; times 20, 35 and 50 min and air velocities 0.5, 1.5 and 2.5 m/s) using Vis/NIR hyperspectral imaging and multivariate analysis. The effects of different pre-processing methods and spectral treatments such as normalization [multiplicative scatter correction (MSC), standard normal variate transformation (SNV)], smoothing (median filter, Savitzky–Golay and Wavelet) and differentiation (first derivative, D1 and second derivative, D2) on the obtained data were investigated. The prediction models were developed by partial least square regression (PLSR) and artificial neural network (ANN). The results indicated that ANN models have higher potential to predict moisture content and textural characteristics of roasted pistachio kernels comparing to PLSR models. High correlation was observed between reflectance data and fracture force (R2 = 0.957 and RMSEP = 3.386) using MSC, Savitzky–Golay and D1, compressive energy (R2 = 0.907 and RMSEP = 15.757) using the combination of MSC, Wavelet and D1, moisture content (R2 = 0.907 and RMSEP = 0.179) and apparent modulus of elasticity (R2 = 0.921 and RMSEP = 2.366) employing combination of SNV, Wavelet and D1, respectively. Moreover, Vis–NIR data correlated well with hardness (R2 = 0.876 and RMSEP = 5.216) using SNV, Wavelet and D2. These results showed the capability of Vis/NIR hyperspectral imaging and the central role of multivariate analysis in developing accurate models for prediction of moisture content and textural properties of roasted pistachio kernels

Antioxidative, antiradical, and antimicrobial activities of extracts from Antep Pistachio hulls

Pistacia vera L. is the only genus of more than ten in Pistacia species consumed as a nut and has commercial value. Turkey is one of the homelands of the pistachio species, and they are named Antep pistachio. When Antep pistachios are processed into nuts, their reddish purple hulls are removed as a waste after the processing. In this research, Antep pistachio hull samples extracted by methanol, ethanol and water were tested for antioxidant and antiradical (IC(50) value) potentials, and antimicrobial activities as well. The values of total phenolic content of methanol extracts of Antep pistachio hull was 167.49 +/- A 0.48 mg gallic acid equivalent (GAE)/g dry extract. The ethanol and aqueous extract of the pistachio hulls were determined as 89.87 +/- A 0.44 and 31.73 +/- A 0.21 mg GAE/g dry extract, respectively. The antioxidant activities of extracts were evaluated by the phosphomolybdenum method. The highest antioxidant activity of the hull extracts was determined in the methanol extracted samples (152.10 +/- A 0.19 mg ascorbic acid equivalent (AAE)/g dry extract), while the lowest value was in the ethanol extracts (15.19 +/- A 0.00 mg AAE/g dry extract). The values of IC(50) in methanol, ethanol and aqueous extracts of the pistachio hulls were 16.01, 21.62 and 24.45 mu g/ml, respectively. The highest antiradical activity was in the methanol extract of Antep pistachio hulls. In this research, the pistachio hull extracts were tested for antimicrobial activities against total 15 microorganisms, 13 bacteria and 2 yeasts. The aqueous extract of the hull was the most ineffective extract against the microorganisms tested. The methanol and ethanol extracts of the pistachio hulls, which had limited antimicrobial effect against the bacteria, Mycobacterium smegmatis, Salmonella typhimurium, Proteus mirabilis and Yersinia enterocolitica, and the yeasts, Saccharomyces cerevisiae and Candida albicans, and were effective on the other microorganisms constituted inhibition zones diameter as between 10 and 39 mm. All extracts of the pistachio hulls exhibited antimicrobial activity against Listeria monocytogenes (6-38 mm) and Escherichia coli O157: H7 (8-28 mm). In conclusion, the hulls of Antep pistachio can be evaluated as a potential antimicrobial and antioxidant resource in the food systems