Ultrastructural and developmental toxicity of potato and tomato leaf extracts to beet armyworm,Spodoptera exigua (lepidoptera: noctuidae)

Beet Armyworm, Spodoptera exigua is a herbivorous moth and a serious pest of many economically important plants, which are used as food sources. Because of rigorous standards of food quality, usage of synthetic insecticides in crop protection, against pests, is limited. Solanaceae plant extracts may be a relatively cheap source of efficient natural insecticides that can limit usage of synthetic substances. Their biological activity is not fully known. In particular, ultrastructural studies, using transmission electron microscopy, are not usual. In the present article we describe the effects of sublethal concentrations of tomato and potato leaf extracts against S. exigua. Acute lethal effects were not observed. Both extracts exerted similar effects within midgut and fat body cells. Midgut cells were not significantly altered while fat body cells showed prominent swelling of nuclear envelope and endoplasmic reticulum, vacuolization of mitochondria and fusion of fat droplets. These changes were much more intensive within groups exposed to potato than tomato extracts at highest concentration at least. Light microscopy was used to observe and document developmental alterations of S. exigua exposed to potato and tomato leaf extracts. Potato leaf extracts significantly decreased hatching success and caused morphological malformations of imagoes. Among them, malformations of wings were the most prominent. Interestingly, these effects were not observed within populations exposed to tomato extracts at highest concentration at least.     

Weissella cibaria short-fermented liquid sourdoughs based on quinoa or amaranth flours as fat replacer in focaccia bread formulation

Production of the traditional Italian Focaccia bread (FcBread) requires reformulation to meet the new rules for healthier foods. We tested the applicability of a short-fermented (15 h) liquid sourdough (LS) (dough yield, DY, 250), obtained using quinoa (Q) or amaranth (Am) flour fermented with a Weissella cibaria strain (C43-11) producing exopolysaccharides (EPS) as fat replacer in yeast-leavened FcBread. The LSs were applied during the FcBread-making process at industrial pilot plant, reducing the added fat amount by 20% (FcBread-QLS and FcBread-AmLS) and products were compared with reference samples not containing EPS. All the products were analysed for physico-chemical properties (pH, TTA, organic acids, protein content and profile, instrumental colour), textural properties, sensory quality and glycemic index. The application of both pseudo-cereal-based W. cibaria LSs in FcBread allowed obtaining products with a reduced amount of fat, increased protein amount, mainly due to the albumin and glutenin/glutelin fractions, reduced glycemic index, improved texture and preserved in the traditional sensory profile of ‘focaccia’.     

Fabrication of Reduced Fat Products by Controlled Heteroaggregation of Oppositely Charged Lipid Droplets

Abstract: This study describes how the rheological properties of colloidal dispersions formed by heteroaggregation of oppositely charged protein‐coated lipid droplets depend on total particle concentration. Mixed‐particle emulsions were formed by mixing single‐particle emulsions containing either β‐lactoglobulin‐coated lipid droplets (ζ≈?42 mV, d₄₃≈ 0.35 μm) or lactoferrin (LF)‐coated lipid droplets (ζ≈+26 mV, d₄₃≈ 0.32 μm). A series of single‐particle and mixed‐particle emulsions with different total fat contents (5% to 40%) were prepared, and their mean particle size, apparent viscosity, and shear modulus were measured. Mixed‐particle emulsions (40% LF: 60%β‐Lg) containing relatively high fat contents (>10%) had high viscosities and paste‐like properties. These rheological characteristics were attributed to extensive particle aggregation and network formation due to electrostatic attraction between oppositely charged droplets. The viscosities of mixed‐particle emulsions were much higher than those of single‐particle emulsions with equivalent fat contents. Measurements of the color coordinates (L*, a*, b*) of mixed‐particle emulsions with low fat contents showed that they had similar appearances as single‐particle emulsions with high fat contents. This study has important implications for the creation of reduced fat foods with similar sensory qualities as higher fat foods. Practical Application: This study describes how novel food materials can be created by mixing together negatively charged and positively charged lipid droplets. These mixed emulsions may be suitable for the creation of reduced fat products, since they have high viscosities and paste‐like properties at relatively low fat contents.     

Viscoelasticity and texture of spreadable cheeses with different fat contents at refrigeration and room temperatures

The effect of the 2 common consumption temperatures, refrigeration temperature (10°C) and room temperature (22°C), on the viscoelasticity, mechanical properties, and perceived texture of commercial cream cheeses was studied. Two samples with different fat contents, regular and low fat, from each of 4 selected commercial brands were analyzed. The selection criteria were based on identification of brands with different percentages of fat content reduction between the regular- and low-fat samples (35, 50, 84, and 98.5%). The fat content of regular-fat samples ranged from 19.8 to 26.0% (wt/wt), and that of low-fat samples ranged from 0.3 to 13.0% (wt/wt). Viscoelasticity was measured in a controlled-stress rheometer using parallel-plate geometry, and the mechanical characteristics of samples were measured using the spreadability test. Differences in the intensity of thickness, creaminess, and roughness between the regular- and low-fat samples of each commercial brand were evaluated at each of the selected temperatures by using the paired comparisons test. At 10°C, all samples showed higher viscoelastic modulus values, firmness, and stickiness, and lower spreadability than when they were measured at 22°C. Differences in viscoelasticity and mechanical properties between each pair of samples of the same brand were greater at 10°C than at 22°C because of the influence not only of fat content but also of fat state. Ingestion temperature did not modify the sensory differences detected between each pair of samples in terms of creaminess and roughness, but it did modify the differences detected in thickness. The joint consideration of sample composition, fat state, and product behavior during oral processing could explain the differences detected in thickness perceived because of measurement temperatures.     

Physico chemical,microstructural and sensory characteristics of low‐fat meat emulsion containing aloe gel as potential fat replacer

In this study, a possible use of aloe gel (AG) as a potential fat replacer in the manufacture of low‐fat meat emulsion was investigated. The low‐fat meat emulsions with added AG and vegetable oil (VO) in different proportions [AG7.5 (7.5% AG + 7.5% VO); AG5 (5% AG + 10% VO); AG2.5 (2.5% AG + 12.5% VO)] were compared with full‐fat meat emulsion [Control (15% VO only)]. A substantial fat reduction (P < 0.05) up to 50% as compared to full‐fat control meat emulsion was recorded without compromising other sensory attributes of meat emulsion. Microstructural properties as studied by scanning electron microscopy indicated more homogenous regular emulsion matrix with fewer cracks and more regular shaped oil droplets in AG‐added samples than the control samples.     

Composition and Structure of the Bovine Milk Fat Globule Membrane—Some Nutritional and Technological Implications

Milk fat is dispersed in milk as small, spherical globules, stabilized in the form of emulsion by its surrounding membrane. This membrane, called the milk fat globule membrane (MFGM), is created in the secretory cells of the mammary gland, and represents an ordered and unique biophysical system. This review characterizes the main milk fat globule components, their structure, and intracellular origin. The milk fat globule membrane has many potentially bioactive components. These are discussed in terms of their health effects for the native and processed globules. Because of their functional and nutritional properties, MFGM components can be used as valuable ingredients in the manufacture of new functional foods.     

Creation of reduced fat foods: Influence of calcium-induced droplet aggregation on microstructure and rheology of mixed food dispersions

The impact of calcium-induced fat droplet aggregation on the microstructure and physicochemical properties of model mixed colloidal dispersions was investigated. These systems consisted of 2 wt% whey protein-coated fat droplets and 4 wt% modified starch granules heated to induce starch swelling (pH 7). Optical and confocal microscopy showed that the fat droplets were dispersed within the interstitial region between the swollen starch granules. The structural organisation of the fat droplets within these interstitial regions could be modulated by controlling the calcium concentration: (i) at a low calcium concentration the droplets were evenly distributed; (ii) at an intermediate calcium concentration they formed a layer around the starch granules; (iii) at a high calcium concentration they formed a network of aggregated droplets. Paste-like materials were produced when the fat droplets formed a three-dimensional network in the interstitial region. The properties of fat droplet–starch granule suspensions can be modulated by altering the electrostatic interactions to alter microstructure.     

A process for the production of a diacylglycerol‐based milk fat analogue

We propose a novel process for the production of a DAG‐rich acylglycerol mixture derived from milk fat. This product has potentially interesting nutritional properties, derived from both its high content of DAG and of short‐chain fatty acids (FAs). The proposed process consists of three steps: lipase‐catalysed partial ethanolysis of milk fat, extraction of the by‐product fatty acid ethyl esters (FAEEs) using supercritical carbon dioxide (SC‐CO₂) and isomerization of DAG to increase the proportion of 1,3‐DAG. The experimental investigation of the process steps was done using milk fat and trilaurin. Several lipases were tested for maximizing the percentage of DAG in the acylglycerol mixture produced by ethanolysis. The selectivity of the chosen lipase was such that the produced AG mixture was enriched in short‐chain FAs in relation to the original milk fat. FAEEs were completely extracted from the ethanolysis mixture by SC‐CO₂. In the final process step, we explored the reaction conditions for facilitating acyl migration in the DAG mixture, so that the equilibrium proportion of 1,3‐DAG (～64%) was attained. Our results set the basis for the development of a simple process for the production of a DAG‐rich milk fat analogue.