Effect of temperature on milk fats of cow,buffalo,and goat used for frying local food products

Objectives:Thermal processes,such as refining and frying,result in the formation of trans fatty acids(TFAs)in edible oils or fats.Concerning the detrimental effect of TFAs on human health,milk fat samples of cow,buffalo,and goat are collected in order to elucidate TFAs accumulation during thermal processing.Methods:The increased amount of TFAs due to heating is analyzed by attenuated total reflection-Fourier transform infrared(ATR-FTIR)spectroscopy in conjunction with second-derivative treatment and gas chromatographic(GC)analysis.Results:The total amount of TFAs has been increased from 7.71 to 8.25 per cent for cow milk fat,7.12 to 7.82 per cent for buffalo milk fat,and from 6.82 to 7.61 per cent for goat milk fat on heating the samples to 125°C-175°C as predicted by GC.Conclusions:Local food products fried in these milk fats are hence very harmful to human health.These results demonstrate that thermally induced TFAs in milk fats are closely related to the process temperature and time,which should be considered to reduce the formation of TFAs during thermal treatment.

Urban Agriculture:A Transitional Mechanism for Reducing Environmental Degradation and Fossil Fuel over Dependence

With the increasing population in the urban cities of the world,the demand for food from distant areas has been on the rise but at the expense of scarce natural resources like oil,water and forest,etc.However,producing food locally in urban centers provides a sustainable mechanism of reducing the carbon,food or ecological footprints of these cities in particular and environmental degradation in general.It creates a circular metabolic system in which the natural inputs are efficiently harnessed rather than the linear metabolic system in which resources flow in and wastes flow out.This article analyzes some urban agricultural local initiatives in urban centers of the worlds that promote a circular metabolic systems and proposes the procedure that can be adopted to promote urban agriculture.

Urban Food Supply under Constrained Land Resources in Beijing:Potential and Optimization

The recent global food security crisis is garnering increasing attention and calls for innovative solutions to mitigate its negative impacts on people, especially the most economically vulnerable. In urban regions, this issue is aggravated by the fact that, on one hand, rapid urbanization and greater levels and diversity of food consumption associated with the growing affluence of urban inhabitants has led to rising urban food demand, while on the other hand, the rapid loss of farmland due to urban expansion or irrational sprawl and increasing extreme weather events for agricultural producers due to the impact of global climate change is sharply reducing the urban food production and local supply capacity. Therefore how to realize the urban food supply potential and optimize the utilization of the urban farmlands to enhance the local food supply rate and improve urban food security more generally is becoming a key issue. In this paper, we use the case of Beijing to examine the opportunities to enhance the supply of local, affordably priced food under existing land resource constraints, by restructuring farmland utilization. In this paper, we firstly calculate the changes in the food footprint needed by Beijing and its food self-sufficiency rate over the thirty year period from 1981 to 2011. We show that although Beijing’s food footprint has grown from 11 800 to 29 400 km2 over this 30-year period, its food self- sufficiency rate has dropped from 59.3%, 35.8%, 37.3% and 13.1% to about 39.0%, 27.0%, 6.7% and 2.2% for vegetable, fruit, grain and edible oil, respectively. Following this analysis, we calculate Beijing’ s potential food production under different agricultural production allocation scenarios. We conclude that with a proper shift of farmland use, full utilization of temporary idle land, and the development of rooftop farming, Beijing could increase its vegetable self-sufficiency rate to 60% without significantly reducing the production of other types of local food. Given the sensitivity of fresh vegetables to long- distance transport, and the potential to reduce transport-related carbon emissions, this is a worthwhile adjustment that will benefit the city both by meeting the growing need of its residents for fresh food, and by improving the overall regional eco-environment.