Cover Image,Volume 97, Issue 15

The cover image, by Rosa Isela Ventura‐Aguilar et al., is based on the Review Cactus stem (Opuntia ficus‐indica Mill): anatomy, physiology and chemical composition with emphasis on its biofunctional properties, DOI: 10.1002/jsfa.8493 .

     

Reduction of Protease Activity in Simulated Milk Ultrafiltrate by Continuous Flow High Intensity Pulsed Electric Field Treatments

A protease from Bacillus subtilis suspended in simulated milk ultrafiltrate (SMUF) was subjected to high intensity pulsed electric field (HIPEF) treatments of up to 6787 kJ/l, applying field strengths ranging from 19.7 to 35.5kV/cm up to 896 μs to evaluate the feasibility of this treatment on inactivating the enzyme. In addition, the influence of the pulse repetition rate (67, 89, and 111 Hz) and pulse width (4 and 7 μs) on the effectiveness of HIPEF treatments was tested. Protease activity was considerably reduced; a maximum inactivation of 62.7% was achieved after an 896‐μS treatment at 35.5 kV/cm and 111 Hz. Protease activity decreased exponentially with increase of input energy density, treatment time, field strength, and pulse repetition rate when exposed to HIPEF processing.     

A Generalized Vision-based Stiffness Controller for Robot Manipulators with Bounded Inputs

Generally, stiffness and impedance control schemes require knowledge of the location of any object with which a robot interacts within its workspace; therefore, the integration of a computer vision system within the control loop allows us to know the location of the robot end effector and the object (target) simultaneously. In this paper, a generalized and saturating vision-based stiffness controller with adaptive gravity compensation is presented. The proposed control algorithm is designed to regulate robot-environment interaction in task-space, where the contact force is modeled as a vector of generalized bounded spring-like forces. In order to control nonredundant robots, the proposed controller has a nonlinear proportional-derivative structure with static model-based compensation of gravitational forces, as it includes a regressor-based adaptive term. To support the proposal, the Lyapunov stability analysis of the closed-loop equilibrium vector is presented. Finally, the suitable performance of the proposed scheme was verified by numerical simulations and experimental tests.

     

Potential of Medicinal Plants as Antimicrobial and Antioxidant Agents in Food Industry: A Hypothesis

Many food preservation strategies can be used for the control of microbial spoilage and oxidation; however, these quality problems are not yet controlled adequately. Although synthetic antimicrobial and antioxidant agents are approved in many countries, the use of natural safe and effective preservatives is a demand of food consumers and producers. This paper proposes medicinal plants, traditionally used to treat health disorders and prevent diseases, as a source of bioactive compounds having food additive properties. Medicinal plants are rich in terpenes and phenolic compounds that present antimicrobial and antioxidant properties; in addition, the literature revealed that these bioactive compounds extracted from other plants have been effective in food systems. In this context, the present hypothesis paper states that bioactive molecules extracted from medicinal plants can be used as antimicrobial and antioxidant additives in the food industry.     

Effect of high hydrostatic pressure to sweet potato flour on dough properties and characteristics of sweet potato‐wheat bread

The effect of high hydrostatic pressure (HHP, 100–400 MPa) for 20 min at 25 °C to sweet potato flour (SPF) on dough properties and characteristics of sweet potato‐wheat bread was investigated. The particle size of SPF after HHP was decreased significantly. The obvious rupture was observed in granules of SPF after HHP at 300 and 400 MPa by scanning electron microscopy (SEM). After HHP, significant differences on endothermic peak temperatures (T_P) of SPF were observed by differential scanning calorimetric (DSC), of which the enthalpy change (ΔH) had a slight increase, expect that at 200 MPa. Gas retention of dough with SPF after HHP increased markedly from 1199 (0.1 MPa) to 1246 ml (100 MPa). Specific loaf volume of bread with SPF at 400 MPa was increased significantly, while the hardness and chewiness were reduced. Thus, SPF treated with HHP at 400 MPa could be potentially used in wheat bread production.     

Fast method for multielemental analysis of plants and discrimination according to the anatomical part by total reflection X-ray fluorescence spectrometry

Fast and reliable analytical methodologies are required for quality control of plants in order to assure human health. Ultrasound-assisted extraction in combination with total reflection X-ray fluorescence is proposed as a fast and simple method for multielemental analysis of plants on a routine basis. For this purpose, five certified reference materials have been analysed for the determination of P, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn and Pb. Different extractant media (acids and oxidants) were tried. A mixture of diluted HNO₃ + HCl + HF, was selected as the best option for the achievement of complete extractions. Accurate and precise results can be reached in most cases along with a high sample throughput. Different plants (i.e., herbs, spices and medicinal plants) were analysed. Linear discriminant analysis together with the elemental concentrations allowed the differentiation of commercial preparations corresponding to flower, fruit and leaf.     

Detection of Myosin 1g Overexpression in Pediatric Leukemia by Novel Monoclonal Antibodies

Myosin 1g (Myo1g) is a mechanoenzyme associated with actin filaments, expressed exclusively in hematopoietic cells, and involved in various cellular functions, including cell migration, adhesion, and membrane trafficking. Despite the importance of Myo1g in distinct functions, there is currently no monoclonal antibody (mAb) against Myo1g. mAbs are helpful tools for the detection of specific antigens in tumor cells and other tissues. The development of mAbs against targeted dysregulated molecules in cancer cells remains a crucial tool for aiding in the diagnosis and the treatment of patients. Using hybridoma technology, we generated a panel of hybridomas specific for Myo1g. ELISA, immunofluorescence, and Western blot assay results revealed the recognition of Myo1g by these novel monoclonal antibodies in normal and transformed T and B cells. Here, we report the development and application of new monoclonal antibodies against Myo1g for their potential use to detect its overexpression in acute lymphoblastic leukemia (ALL) patients.     

Effects of high intensity pulsed electric field and thermal treatments on a lipase from Pseudomonas fluorescens

Milk and dairy products may contain microorganisms capable of secreting lipases that cause sensory defects and technological problems in the dairy industry. In this study, the effects of thermal and high-intensity pulsed electric field (HIPEF) treatments on an extracellular lipase from Pseudomonas fluorescens, suspended in a simulated skim milk ultrafiltrate (SMUF) have been evaluated. Heat treatments applied were up to 30 min from 50 to 90 degrees C. HIPEF treatments were carried out using pilot plant facilities in a batch or continuous flow mode, where treatment chambers consisted of parallel and coaxial configuration, respectively. Samples were subjected to up to 80 pulses at electric field intensities ranging from 16.4 to 37.3 kV/cm. This resulted in a lipase that was quite resistant to heat and also to HIPEF. High (75 degrees C-15 s) and low pasteurization treatments (63 degrees C-30 min) led to inactivations of 5 and 20%, respectively. Using the batch-mode HIPEF equipment, a 62.1% maximum activity depletion was achieved after 80 pulses at 27.4 kV/cm. However, when HIPEF treatments were applied in the continuous flow mode, an inactivation rate of just 13% was achieved, after applying 80 pulses at 37.3 kV/cm and 3.5 Hz. The results of both heat and HIPEF treatments on enzyme inactivation were adjusted with good agreement to a first-order kinetic model (R2 > 62.3%).     

Fast determination of arsenic,selenium, nickel and vanadium in fish and shellfish by electrothermal atomic absorption spectrometry following ultrasound-assisted extraction

Ultrasound-assisted extraction of As, Se, Ni and V from fish and shellfish has been applied as a fast and reliable sample pre-treatment method for accurate determination of the four elements by electrothermal atomic absorption spectrometry with Zeeman (As, Se) or Deuterium (Ni, V) background correction. A multivariate optimization approach has been employed for establishing the effect of variables influencing the extraction process. Under suitable conditions, quantitative extractions occurred from a 10 mass sample (particle size <100 μm) suspended in 1.5 mL of acidic extractant (0.5 or 3% v/v HNO₃) and subjected to high intensity ultrasound (50% amplitude; 3 min). The method was successfully validated against the following certified reference materials: NRCC-DORM-2 dogfish muscle, NRCC-DOLT-2 dogfish liver, NRCC-TORT-2 lobster hepatopancreas, NIST-SRM 1566b oyster tissue and BCR 627 tuna fish. The following seafood samples were analyzed: hake (Merluccius merluccius), sole (Solea solea), clam (Venerupis rhomboides), prawn (Panaeus kerathurus), cuttlefish (Sepia officinalis), shrimp (Palaemon elegans), razor shell (Ensis ensis), cockle (Cardium edule), Mussel (Mytilus galloprovincialis), edible crab (Cancer pagurus), meagrin (Lepidorhombus whiffiagonis). The concentration ranges (μg/g, dry weight) for the elements determined were as follows: As (12.6–190), Se (0.73–2.34), Ni (2.94–46) and V (0.82–5.14). The detection limits (LODs), defined as 3s/m (s being the standard deviation of 10 blank and m the slope of the calibration graph), in dry tissue were 0.6, 0.3, 0.2 and 0.4 μg/g for As, Se, Ni and V, respectively. Between-batch precision was expressed as relative standard deviation from three separate extractions was in the range 3–10%.