Data and Models of Water Activity. II

2009 ◽  
Author(s):  
Piotr Lewicki
Keyword(s):  
Water Activity

Obtaining and Characterisation of Starch-Based Edible Films Incorporating Honey, Propolis and Bee Bread

2019 ◽  
Vol 23 (2) ◽  
pp. 193-198
Author(s):  
Monica Mironescu ◽  
Laura Fratila ◽  
Alexandru Hupert ◽  
Ion Dan Mironescu
Keyword(s):  
Water Activity ◽  
Mechanical Characteristics ◽  
Edible Films ◽  
Ash Content ◽  
Colour Intensity ◽  
Sensorial Analysis ◽  
Physical Chemical ◽  
Control Film ◽  
Bee Bread

Abstract This research investigates the physical-chemical, sensorial and mechanical characteristics of starch-based edible films incorporating three types of bee hive products: honey, propolis and bee bread, in concentrations varying from 1% to 3%, reported to starch. The results indicates an increasing of films moisture, water activity, ash content and acidity, in the order: honey<propolis<bee bread, all values increasing with the increasing of hive products percentage into the control film; aw is remaining at very low values, under 0.4. Sensorial analysis indicated honey as the better suited for improving taste and flavour and bee bread for increasing colour intensity of the films; the sensorial characteristics are maintained during 30 days of films storage, in all cases. Compared with the control starch-based film (which is elastic, brittle and hard), the films containing 2% bee hive products are elasto-plastic and more resistant to penetration, the resistance increasing in the order: bee bread<propolis<honey.

scholarly journals Chemical and Physical Properties of Some Hazelnut Varieties Grown in Portugal

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1476
Author(s):  
Ana Cristina Ferrão ◽  
Raquel P. F. Guiné ◽  
Elsa Ramalhosa ◽  
Arminda Lopes ◽  
Cláudia Rodrigues ◽  
...  
Keyword(s):  
Discriminant Analysis ◽  
Physical Properties ◽  
Water Activity ◽  
Induction Time ◽  
Oxidation Stability ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Nutritional Characteristics ◽  
Physical And Chemical ◽  
And Chemical Properties

Hazelnuts are one of the most appreciated nuts worldwide due to their unique organoleptic and nutritional characteristics. The present work intended to analyse several physical and chemical properties of different hazelnut varieties grown in Portugal, namely Tonda de Giffoni, Grada de Viseu, Segorbe, Longa de Espanha, Butler, Gunslebert, and Negreta. In general, the results revealed statistically significant differences between the varieties under study. The Gunslebert had more elongated hazelnuts and with heavier shelled fruits, while the kernels of the Grada de Viseu revealed to be heavier. Grada de Viseu was harder in the shell, Gunslebert had a harder core, and Segorbe was more resistant to fracture. Fat was the more representative component for all varieties and in some cases the values of moisture and water activity were over the recommended amount (≥0.62). Tonda de Giffoni was the variety with the highest induction time, indicating the highest oxidation stability. Moreover, discriminant analysis revealed that the variables more important to distinguish the varieties were protein (λ = 0.007) and water activity (λ = 0.010). The results of this study help to better understand the differences between some hazelnut varieties that are cultivated in Portugal, which gives important hints for all players in the hazelnut sector.

scholarly journals Decontamination of Powdery Foods Using an Intense Pulsed Light (IPL) Device for Practical Application

2021 ◽  
Vol 11 (4) ◽  
pp. 1518
Author(s):  
Hee-Jeong Hwang ◽  
So-Yoon Yee ◽  
Myong-Soo Chung
Keyword(s):  
Total Energy ◽  
Water Activity ◽  
Treatment Time ◽  
Sesame Seed ◽  
Pilot Scale ◽  
Black Pepper ◽  
Intense Pulsed Light ◽  
Pulsed Light ◽  
Energy Fluence ◽  
Color Changes

Controlling microbial problems when processing seeds and powdered foods is difficult due to their low water activity, irregular surfaces, and opaqueness. Moreover, existing thermal processing can readily cause various undesirable changes in sensory properties. Intense pulsed light (IPL) can be effective in nonthermal processing, and so two xenon lamps were attached to the sides of a self-designed cyclone type of pilot-scale IPL device. Each lamp was connected to its own power supply, and the following treatment conditions were applied to four sample types: lamp DC voltage of 1800–4200 V, pulse width of 0.5–1.0 ms, frequency of 2 Hz, and treatment time of 1–5 min. This device achieved reductions of 0.45, 0.66, and 0.88 log CFU/mL for ground black pepper, red pepper, and embryo buds of rice, respectively, under a total energy fluence of 12.31 J/cm2. Meanwhile, >3-log reductions were achieved for sesame seed samples under a total energy fluence of 11.26 J/cm2. In addition, analyses of color changes, water activity, and moisture content revealed no significant differences between the control and IPL-treated samples. These findings indicate that IPL treatment may be considered a feasible sterilization method for seeds and powdered foods.

scholarly journals The effect of functional additives on the indicator “water activity” of biscuit semi-finished products

2021 ◽  
Vol 640 (2) ◽  
pp. 022022
Author(s):  
E S Belokurova ◽  
I A Pankina ◽  
A D Sevastianova ◽  
I V Asfondiarova ◽  
N M Katkova
Keyword(s):  
Water Activity ◽  
Functional Additives

A Wide Range Ge Gamma-Ray Spectrometer for on-Line Measurements of Reactor Cooling Water Activity

1977 ◽  
Vol 24 (1) ◽  
pp. 673-677 ◽  
Author(s):  
J. J. Lipsett ◽  
I. L. Fowler ◽  
R. J. Dinger ◽  
H. L. Malm
Keyword(s):  
Water Activity ◽  
Gamma Ray ◽  
Cooling Water ◽  
Gamma Ray Spectrometer ◽  
Wide Range ◽  
On Line
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