Structure, controlled release mechanisms and health benefits of pectins as an encapsulation material for bioactive food components.

Encapsulation of food and feed ingredients is commonly applied to avoid the loss of functionality of bioactive food ingredients. Components that are encapsulated are usually sensitive to light, pH, oxygen or highly volatile. Also, encapsulation is also applied for ingredients that might influence taste. Many polymers from natural sources have been tested for encapsulation of foods. In the past few years, pectins have been proposed as emerging broadly applicable encapsulation materials. The reasons are that pectins are versatile and inexpensive, can be tailored to meet specific demands and provide health benefits. Emerging new insight into the chemical structure and related health benefits of pectins opens new avenues to use pectins in food and feed. To provide insight into their application potential, we review the current knowledge on the structural features of different pectins, their production and tailoring process for use in microencapsulation and gelation, and the impact of the pectin structure on health benefits and release properties in the gut, as well as processing technologies for pectin-based encapsulation systems with tailor-made functionalities. This is reviewed in view of application of pectins for microencapsulation of different sensitive food components. Although some critical factors such as tuning of controlled release of cargo in the intestine and the impact of the pectin production process on the molecular structure of pectin still need more study, current insight is that pectins provide many advantages for encapsulation of bioactive food and feed ingredients and are cost-effective.

Pesticide residues in raw and processed maize grains and flour from selected areas in Dar es Salaam and Ruvuma, Tanzania.

This study investigated the levels of pesticide residues in maize grains and flour and the effects of processing methods on their levels in maize products in samples collected in Dar es Salaam and Ruvuma regions. Analysis of cleaned-up extracts was done using gas chromatography-mass spectrometry (GC-MS). Twelve pesticides were detected in maize grains and their highest concentrations were up to 676.1, 11200 and 14 µg/kg for organochlorines, organophosphorous and pyrethroid pesticides, respectively. In maize flour, eight pesticides were detected and the concentrations for organochlorines, organophosphorous and pyrethroid pesticides were up to 333.3, 2220 and 2 µg/kg, respectively. Only dieldrin was detected in cooked samples at a concentration of 2 µg/kg. The concentrations of p,p'-DDD, aldrin, dieldrin, chlorpyrifos and pirimiphos methyl in some grains and flour samples exceeded the maximum residue limit (MRLs). The findings indicate risks and concerns for public health. Processing methods were found to cause transformation and reduction of the pesticides.

Characterization of flavor modulating effects in complex mixtures via high temperature liquid chromatography.

The identification of flavor modulating compounds, for example, bitter masking or sweet enhancing compounds, in complex mixtures such as botanical extracts or food preparations is difficult and time- and work-intensive. To accelerate this process, an improved screening method was developed on the basis of the separation of complex matrixes by the so-called LC Taste setup and subsequent comparative sensory analysis. The eluent containing only water and ethanol was diluted with a basic tastant solution (500 mg L(-1) caffeine and 5% sucrose, respectively) and evaluated by a trained panel by duo comparison tests. This novel method was applied to the known flavor and taste modulating substances homoeriodictyol (1), sterubin (2), hesperetin (3), and lactisol (9) as well as to simple mixtures of homoeriodictyol (1), sterubin (2), and hesperetin (3). To evaluate the potential of the method for more complex matrixes, the protocol was applied to plant extracts from Yerba Santa (Eriodictyon californicum) and honeybush tea (Cyclopia intermedia). The flavor modulating activities reported for homoeriodictyol (1), sterubin (2), and hesperetin (3) could be confirmed in these complex mixtures.