Feasibility of Using Electrical Impedance Spectroscopy for Assessing Biological Cell Damage during Freezing and Thawing.

This study was performed to test bioimpedance as a tool to detect the effect of different thawing methods on meat quality to aid in the eventual creation of an electric impedance-based food quality monitoring system. The electric impedance was measured for fresh pork, thawed pork, and during quick and slow thawing. A clear difference was observed between fresh and thawed samples for both impedance parameters. Impedance was different between the fresh and the frozen-thawed samples, but there were no impedance differences between frozen-thawed samples and the ones that were frozen-thawed and then stored at +3 °C for an additional 16 h after thawing. The phase angle was also different between fresh and the frozen-thawed samples. At high frequency, there were small, but clear phase angle differences between frozen-thawed samples and the samples that were frozen-thawed and subsequently stored for more than 16 h at +3 °C. Furthermore, the deep learning model LSTM-RNN (long short-term memory recurrent neural network) was found to be a promising way to classify the different methods of thawing.

Identifying labelling and marketing advantages of nutrients in minced beef meat: A case study.

In 2006, the European Commission approved nutrition and health claim regulations of foods to stimulate healthier choices. To document how commercial, minced beef meat complied with regulations, meat samples from 72 carcasses were analysed. These samples were a source of niacin (B3), pyridoxine (B6), phosphorus and iron (cow meat only), and a rich source of protein, monounsaturated fat, vitamin B12 and zinc. A potential exists for establishing beef meat as a source of vitamin K, iron and selenium. The meat's nutrient relevance for young women when ingesting 150 g of raw beef mince/day was estimated. Increased levels of riboflavin (B2), pantothenic acid (B5), iron and selenium beyond presently observed, would better support this group's recommended nutrient intake. If the bioactivity of 25-OH-vitamin D3 could be used in calculations, vitamin D3 in the minced meat would add positively to the intake of vitamin D3 that was 49% of the recommended intake.

Detectability of the degree of freeze damage in meat depends on analytic-tool selection.

Novel freezing solutions are constantly being developed to reduce quality loss in meat production chains. However, there is limited focus on identifying the sensitive analytical tools needed to directly validate product changes that result from potential improvements in freezing technology. To benchmark analytical tools relevant to meat research and production, we froze pork samples using traditional (-25 °C, -35 °C) and cryogenic freezing (-196 °C). Three classes of analyses were tested for their capacity to separate different freeze treatments: thaw loss testing, bioelectrical spectroscopy (nuclear magnetic resonance, microwave, bioimpedance) and low-temperature microscopy (cryo-SEM). A general effect of freeze treatment was detected with all bioelectrical methods. Yet, only cryo-SEM resolved quality differences between all freeze treatments, not only between cryogenic and traditional freezing. The detection sensitivity with cryo-SEM may be explained by testing meat directly in the frozen state without prior defrosting. We discuss advantages, shortcomings and cost factors in using analytical tools for quality monitoring in the meat sector.

Monitoring lean meat percentage predictions from optical grading probes by a commercial cutting pattern.

The lean meat percentage (LMP) classification in Norwegian slaughterhouses is obtained by Hennessy Grading Probe 7 (HGP7), an optical tool. Even though the HGP7 method is validated frequently, there is industrial and legislative demand to reconsider the applied LMP equation, typically due to the introduction of new breeds. A deboning pilot plant generates precise yield data using cutting and deboning stratified pork carcasses by a specific commercial cutting pattern (CCP) at an annual rate of approximately 250 slaughter pigs. This paper shows how results obtained by CCP can be used to measure LMP in pork and how these results can be used for monitoring the quality of LMP predicted by HGP7. The effect of gender, maternal- and paternal lines on validity of HGP7 predictions was evaluated. The effect of introducing a new maternal line (TN70) seems to be substantial, whereas the effects of the tested paternal lines are small to negligible.

Vitamin C, total phenolics and antioxidative activity in tip-cut green beans (Phaseolus vulgaris) and swede rods (Brassica napus var. napobrassica) processed by methods used in catering.

BACKGROUND: Retention of nutrients in vegetables during blanching/freezing, cooking and warm-holding is crucial in the preparation of both standard and therapeutic diets. In the present study, conventional cooking in water, and cooking by pouch technology (boil-in-bag, sous vide) were compared in their ability to retain vitamin C, total phenolics and antioxidative activity (DPPH and FRAP) in industrially blanched/frozen tip-cut green beans and swede rods. RESULTS: After conventional cooking, 50.4% total ascorbic acid, 76.7% total phenolics, 55.7% DPPH and 59.0% FRAP were recovered in the drained beans. After boil-in-bag cooking, significantly (P < 0.05) higher recoveries were obtained, i.e. 80.5% total ascorbic acid, 89.2% total phenolics, 94.8% DPPH and 92.9% FRAP. Recoveries after sous vide cooking were comparable to those of boil-in-bag cooking. By conventional cooking, 13.5-42.8% of the nutrients leaked into the cooking water; by sous vide about 10% leaked to the exuded liquid, while no leakage occurred by boil-in-bag cooking. Warm-holding beans after cooking reduced recoveries in all components. Recoveries in swede rods were comparable but overall slightly lower. CONCLUSION: Industrially blanched/frozen vegetables should preferably be cooked by pouch technology, rather than conventional cooking in water. Including cooking water or exuded liquid into the final dish will increase the level of nutrients in a meal. Warm-holding of vegetables after cooking should be avoided.

Quality changes of prerigor filleted Atlantic salmon (Salmo salar L.) packaged in modified atmosphere using CO2 emitter, traditional MAP, and vacuum.

Pieces of prerigor salmon fillets were packaged in modified atmosphere (60% CO(2) and 40% N(2)) and in vacuum. The MA packages had a gas to product volume ratio (g/p ratio) of 3/1 (traditional MAP) and 1/1 (packaged with a CO(2) emitter). All the samples were stored at 1.2 degrees C for 25 d. The MA packages had lower bacterial growth during storage compared to vacuum packages. The analyses of 16S rRNA at day 22 indicated a similar bacterial diversity, independent of packaging methods, dominated by Photobacterium phosphoreum. The results therefore suggest that CO(2) inhibited total bacterial count, including, P. phosphoreum. Negative odors and liquid losses were detected earlier for the vacuum-packaged samples (8 d) compared to the MA samples (15 d) and higher levels were detected at the end of the storage period. The breaking strength (firmness) tended to be lower for the MA packaged samples compared with the vacuum samples after 15 d of storage, whereas the redness (a* value) and the yellowness (b* value) were significantly higher for the MA samples. In conclusion, MA packaging preserved the quality better during storage than vacuum packaging. MA packaging with a CO(2) emitter and reduced g/p ratio gave similar or better results compared with traditional MAP, thus CO(2) emitters are well suited for reduction of volume of MA packaged farmed salmon fillet pieces.