Effects of hazelnut skin addition on the cooking, antioxidant and sensory properties of chicken burgers.

The aim was to evaluate the effects of hazelnut skin (HS) addition on the oxidation and sensorial properties of chicken burgers during storage and after cooking. Burgers were prepared and divided in five groups: [C] control without HS addition, [CAA] control with ascorbic acid, and [HS1] 1%, [HS2] 2% and [HS3] 3% HS addition. Burgers for each batch were prepared in triplicate and analysed raw and cooked after 1 and 4 days of refrigerated storage (4 ± 1 °C), respectively. Lipid oxidation was assessed by monitoring malonaldehyde formation with a 2-thiobarbituric acid reactive substances assay, and antioxidant capacity was assessed with 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods. A sensory evaluation was performed by twenty experienced panellists, and the attributes that were measured were: colour, greasiness, flavour, odour, juiciness, granulosity, chewiness and overall acceptability. Lipid oxidation values were higher in the HS burgers than in the C and CAA burgers, except for the cooked burgers at day 4. HS addition had a significant effect with a decrease in diameter and an increase in fat retention. In all treatments, FRAP was lower in the C and HS groups than in the CAA group, except for cooked burgers at day 4, where the values of the HS2, HS3 and CAA groups were similar. The DPPH assay showed higher values on both days for the raw and cooked burgers treated with CAA or HS compared to the control group. HS addition influenced only meat colour among the sensorial parameters that were considered.

Effects of "fresh mechanically deboned meat" inclusion on nutritional value, palatability, shelf-life microbiological risk and digestibility in dry dog food.

Fresh mechanically deboned meat (MDM) is usually claimed as high-quality ingredient on dry pet food recipes and this aspect may positively influence consumer choice. It is important to determine the scientifically sustainability of this claim and to assess the microbiological safety of MDM inclusion in dry pet food. Objectives were: 1) to evaluate the effect of inclusion of MDM in dry dog food on fatty acid profile and in vivo and in vitro digestibility, proposing a new system (DaisyII Incubator) to measure the in vitro digestibility for dogs; 2) to compare palatability of dry dog food containing MDM with dry dog food in which meat by-products (MBP) are the only animal protein sources; 3) to determine, whether or not, the inclusion of that ingredient changes the microbiology and the storage quality. Results indicated that MDM product was characterized by significant higher nutritional value in terms of fatty acids profile, in vitro digestibility (HV-IVD method) and lower palatability than the MBP product. Microbiological risk assessment showed no microbiological hazards for either product. After 6-months storage, the total mesophilic bacterial count ranged between 1.77 and 2.09 log CFU/g feed, while polyamine values were higher in the MDM (0.37 g/kg) than in the MBP (0.27 g/kg). The DaisyII Incubator was found to be a valid instrument for studying in vitro digestibility also for dogs, providing data simply, quickly, with less variability and costs than in vivo trials. In conclusion, MDM inclusion in dry dog food is microbiologically safe and it can improve its nutritional quality, at the expense of a reduced palatability. The higher polyamine levels fount in MDM-enriched petfood after 6-months storage, however, may represent a possible hazard, and further studies are still warranted.

Antioxidant Activity and Phenolic Composition of Amaranth (Amaranthus caudatus) during Plant Growth.

The antioxidant activity and phenolic composition of the aerial part of Amaranthus caudatus at seven stages of development were investigated. Total phenolic content, ABTS•+, DPPH•, and O2•- scavenging activity, ferric-reducing antioxidant power (FRAP), and Fe2+ chelating ability were evaluated. The phenolic profile was characterized by 17 compounds. Rutin was predominant in all growth stages, although its content, similar to the quantity of other phenolics, changed during the growth cycle. Flavonols were most abundant in the plants of early flowering and grain fill stages. In contrast, the highest content of hydroxycinnamic acid derivatives was found in the early vegetative stage. The results of antioxidant assays also showed significant differences among plant stages. Generally, the lowest antioxidant activity was found in the shooting and budding stages. Significantly higher activity was observed in amaranths in earlier (vegetative) and later (early flowering and grain fill) stages, suggesting that plants in these stages are valuable sources of antioxidants.

Antioxidative activities and phenolic compounds of pumpkin (Cucurbita pepo) seeds and amaranth (Amaranthus caudatus) grain extracts.

Phenolic compounds were extracted from pumpkin (Cucurbita pepo) seed and amaranth (Amaranthus caudatus) grain into 80% (v/v) methanol. The extracts obtained were characterised by the contents of total phenolic compounds (TPC), trolox equivalent antioxidant capacity (TEAC), ferric-reducing antioxidant power (FRAP) and antiradical activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH·) radical. The content of individual phenolic compounds was determined by HPLC-DAD method. Pumpkin seeds showed the higher content of TPC than that from amaranth. The TEAC values of both extracts were similar each other. The lower value of FRAP was observed for pumpkin seed. Phenolic compound present in amaranth grain exhibited strongest antiradical properties against DPPH radical. Several peaks were present on the HPLC chromatograms of two extracts. The UV-DAD spectra confirmed the presence of vanillic acid derivatives in the amaranth grain. The three main phenolic compound present in pumpkin seed were characterised by UV-DAD spectra with maximum at 258, 266 and 278 nm.