Martina Foschia

Synergistic effect of different dietary fibres in pasta on in vitro starch digestion

Pasta is traditionally manufactured using only durum wheat semolina, but it is possible to incorporate other flours or ingredients into pasta in order to increase its nutritional value to the consumer, compared to conventional pasta. For this reason, pasta was prepared substituting durum wheat semolina with 15% of enriched dietary fibre flours (Glucagel, inulin Raftiline® HPX, inulin Raftiline® GR, psyllium and oat). Moreover, all dietary fibres (excluded Glucagel) were added in combination in order to evaluate their possible antagonistic or synergic effect on predicted glycaemic response. In general, all enriched dietary fibre pasta sample showed a significant decrease (except for pasta containing a combination of 7.5% inulin Raftiline® GR and 7.5% oat bran flour) in reducing sugars released and standardised AUC values compared to control pasta. However, this study showed that the combination of dietary fibres in pasta formulation led to an antagonistic effect on the predicted glycaemic response.

Influence of hydroponic and soil cultivation on quality and shelf life of ready‐to‐eat lamb's lettuce (Valerianella locusta L. Laterr)

BACKGROUND Nowadays, there is an increasing interest in the hydroponic floating system to cultivate leafy vegetables for ready-to-eat salads. It is reasonable that different growing systems could affect the quality and shelf life of these salads. RESULTS The quality and shelf life of ready-to-eat lambs lettuce grown in protected environment in soil plot or in soil-less system over hydroponic solution with or without the addition of 30 µmol L⁻¹ silicon were evaluated. Minimum effects were observed on colour, firmness and microbial counts. Hydroponic cultivation largely affected plant tissue hydration, leading to weight loss and structural modifications during refrigerated storage. The shelf life of lambs lettuce was limited by the development of visually detectable unpleasant sensory properties. Shelf life, calculated by survival analysis of consumer acceptability data, resulted about 7 days for soil-cultivated salad and 2 days for the hydroponically grown ones. The addition of silicon to the hydroponic solution resulted in an interesting strategy to increase plant tissue yield and reduce nitrate accumulation. CONCLUSIONS Although hydroponic cultivation may have critical consequences on product quality and shelf life, these disadvantages could be largely counterbalance by increased yield and a reduction of nitrate accumulation when cultivation is performed on nutritive solutions with supplemental addition of silicon.

Evaluation of the physicochemical properties of gluten‐free pasta enriched with resistant starch

BACKGROUND The objective was to examine the potential use of resistant starch (RS) as a fibre-enriching ingredient in gluten-free pasta. Pasta was enriched with commercial RS type II (Hi-Maize™ 260) at 100-200 g kg-1 substitution of rice flour. The effects on the rheological properties of dough and pasta quality as a result of RS addition and the loss in RS due to the process were evaluated. RESULTS Dough water absorption was not influenced by the addition of RS. The cooking loss (CL) of RS-enriched samples was 30% lower than reference without fibre. The addition of RS significantly increased firmness of cooked pasta, and above 100 g kg-1 RS level of substitution samples showed a lower stickiness value. Dynamic rheological tests on pasta dough showed a higher storage modulus for fibre samples, indicating a higher number of elastically physical interactions. Loss in RS in uncooked pasta was about 31% compared with the initial amount added to the product. CONCLUSIONS The addition of RS improved the quality of gluten-free pasta owing to its ability to increase the firmness and decrease the CL and stickiness of cooked pasta. The product enriched with 200 g kg-1 RS can be considered a source of DF.

Effect of low-temperature long-time pre-treatment of wheat on acrylamide concentration in short dough biscuits

In April 2002, unexpected high levels of the neurotoxic and suspected carcinogen acrylamide (AA) were found in many heated foods, mainly represented by cereal and potato derivatives. Since then, due to the great consumption of dietary sources of AA among people of different ages and in different countries, worldwide efforts have been carried out to reduce the formation of the toxic molecule in foods. In this paper, the effect of a low-temperature long-time pre-treatment of wheat grains on AA formation in biscuits was investigated. Wheat grains were subjected to heating at 100 degrees C for 8 h and subsequently milled. The obtained flour was used to prepare biscuits that were compared for AA content, texture and color with control samples obtained by using flour from unheated wheat. The low-temperature long-time pre-treatment was responsible for a great decrease (up to 42%) in AA levels in the biscuits, without causing significant changes in the color and texture parameters. As the pre-treatment did not cause any change in sugar and asparagine concentrations, such a reduction in AA concentration can be attributed to a difference in the thermal effect generated in the biscuits obtained by using the unheated and pre-heated flours. In fact, as the heating pre-treatment caused a 2% moisture decrease in the flour, less time at the same temperature was required to obtain biscuits with comparable moisture contents.