Onion skin is a waste produced during onion bulb processing. Recent studies have reported that it contains large amounts of bioaccessible and bioavailable compounds thus it can be used to design of novel food products. The objective of the study was an attempt to substitute semolina with onion skin (OS) powder in pasta at 2.5, 5 and 7.5 g/100 g levels. The effects on the chemical composition, antioxidant potential, technological and sensory properties of the fortified pasta samples were evaluated compared with a control sample. Fortification with OS resulted in a significant (P < 0.05) improvement in nutritional properties, which was demonstrated by an increase in the content of dietary fibre, ash, total phenolic compounds, flavonoids content and antioxidant activity (FRAP and DPPH). Cooking loss increased with increasing levels of OS, however, all pasta samples were in the acceptable range (8 g/100 g). Onion skin incorporation decreased optimal cooking time, water solubility index and increase redness (a*), compared to the control sample. Results of sensory evaluation suggest that pasta, in which 2.5% of the flour was replaced by this plant component, showed the highest value of the “overall quality”. Our study indicates that onion skin powder can be a potential alternative for the food industry to provide nutritional enriched pasta.

Adequate nutrition in prisons should constantly be monitored due to the limited possibilities of external control as well as the low catering budget for prison meals and poorly defined requirements in this regard. The aim of the study was to assess the nutritional value of meals served in Polish prisons. Using a computer program, 14-day regular and bland diets from 30 prisons were analyzed. The energy value of the meals and the percentage of energy provided by protein, fat, and carbohydrate contained therein were found to meet the recommendations of the Polish National Food and Nutrition Institute. The amount of minerals supplied with the diet did not cover the recommended dietary allowance (RDA) in the case of calcium and magnesium. Particularly disturbing was the excessive supply of sodium in the regular and bland diets, which covered 537% and 311% of the dietary reference intake (DRI), respectively, as well as phosphorus (194 and 192% of RDA). The largest vitamin deficiencies were recorded for vitamins D and C and folate. An especially excessive supply was observed for vitamins A and B₁₂. The type of diet significantly differentiated the average content of over half of the analyzed components, whereas the season of the year turned out to be statistically insignificant. The results of the present investigations indicate a need for development of more accurate legal provisions to regulate the nutrition in Polish prisons in terms of not only the energy value and macronutrient supply but also the intake of minerals and vitamins.

In recent years, food industries have produced a large volume of waste, which is an ecological and economic problem. Fruit and vegetable by-products can also be promising sources of functional compounds, with documented pro-health potential. The goal of the study was to evaluate the impact of the addition of various concentrations of onion skin powder on the antioxidant and anti-inflammatory properties associated with changes in the quercetin content in uncooked and cooked pastas. The total contents of phenolic acids, quercetin, and antioxidant activity were determined. The anti-inflammatory activity was demonstrated by inhibitory effects on lipoxygenase (LOX) in vitro activity. Dry onion skin is the source of quercetin in analyzed pastas. The concentrations of these compounds gradually and significantly increased with increases in the vegetable component in fortified pastas. Additionally, a positive correlation between the content of phenolic compounds and antioxidant activity of pastas fortified with onion skin powder was noted. The process of cooking caused enhancement in the antioxidant and anti-inflammatory potential. These qualities of pastas resulted from the presence of dry onion skin with high pro-health activities. Fortification of pasta with onion skin powder could be a starting point to benefit onion industrial by-products and produce new healthy food products.