Results 2023

ABSTRACT - The objective of this study has been to verify whether a combination of the standard Texture Profile Analysis and the back extrusion, which we have named “TPAH” since the analysis was performed after homogenisation, can be applied to products that are difficult to handle. The TPAH was applied to 180 samples, divided equally into eighteen batches of home-made pea-based patties, commercially pea-based patties, and meat patties. Seven TPAH parameters were measured on both raw and cooked samples: adhesiveness, chewiness, cohesiveness, gumminess, hardness, springiness and resilience. The specific density of the raw and cooked samples as well as a few physico-chemical parameters were also measured. All TPAH parameters were able to clearly discriminate between home-made, commercial, and meat patties (P-value<0.05 to 0.001). A Canonical Discriminant Analysis highlighted the effectiveness of TPAH on both raw patties (R2=0.960, Wilks’ Lamba test Pr<0.0001) and cooked ones (R2=0.955, Wilks’ Lamba test Pr<0.0001). Even when the Canonical Discriminant Analysis was narrowed to cooked plant-based patties, the method proved to be efficient (R2=0.809, Wilks’ Lamba test Pr<0.0001). The protein content was significantly related to all the TPAH parameters, except for adhesiveness. The TPAH method could be useful in research related to the substitution of meat patties with plant-based ones. 

Abstract -  In vitro methods have been standardized and tested to correctly simulate the rumen environment and fermentation process. A few studies have verified that the feed degradability achieved as a result of stirring the samples is higher when the samples are incubated under continuous stirring than when they are only stirred twice daily. The objective of this study has been to verify the effect of the speed of stirring on feed degradability during In vitro incubation. For this purpose, the apparent and true dry matter degradability (ADMD and TDMD) of grass hay, pelleted alfalfa, corn silage, barley meal, straw, and a total mixed ration (TMR) were measured after 48 h of incubation in jars under different rotation speeds. The same types of feed were placed in the four jars of each instrument, and the rotation system of the machine was modified to ensure the simultaneous rotation of a pair of original jars (which sometimes stopped and/or rotated slowly and irregularly) together with a pair of modified jars under regular and continuous rotation. A rev counter data logger was mounted onto the jars, and the rotation speeds of the original and modified jars were measured and compared under different conditions (empty jars, jars with liquid, jars with rumen fluid, and sample bags). The modifications to the instruments stabilized the rotation of the jars, thereby making the stirring more regular during incubation. The degradability was partly influenced by the regular stirring, albeit with just one instrument, and for grass hay, barley meal, corn silage, and TMR. In short, it has been found that the regular stirring of sample bags is not essential to obtain reliable degradability measurement during incubation, although it is better to maintain a constant rotation to ensure a regular and standardized In vitro incubation process and therefore to allow reproducibility and comparisons of the results on feed degradability.

Abstract - The demand for milk and meat is continuously increasing with the growth of world population, that is expected to reach about 9.7 billion by 2050. Ruminants are one of the main sources of these animal products, thus boosting their intensive livestock. However, ruminants are exposed to a huge number of contaminants, with potential risks for humans. Among contaminants, plastic materials are probably the most common. Low-density polyethylene (LDPE) and polyamide copolymer (PA-LDPE) films are widely used to cover horizontal silos and to wrap and tie bales; veterinary medicine containers are made of high-density polyethylene (HDPE). In addition, plastics from atmospheric deposition should be accounted in feed contamination studies. Plastics undergo to a systematic fragmentation driven mainly by ultraviolet radiation (UV) and mechanical abrasion, thus generating small plastic fragments (< 5 mm), called microplastics (MPs). Recent studies have shown that MPs can potentially contaminate animal feeds, as confirmed by their presence in cow blood and sheep feces. 

Aim of this work was to verify the presence of MPs in a total mixed ration (TMR) for dairy cows using a protocol specifically optimised to extract 5 polymers: LDPE, HDPE, PA, polyethylene terephthalate (PET) and polystyrene (PS). 

The TMR was sampled in 3 different points of the feed lane of a dairy cattle farm located near Torino (N-W Italy). No plastic disposables or materials were used for sampling or analysis. Samples were dried at 60°C overnight and grounded with a mill (5 mm sieve). The MPs extraction was done with an environmental control blank using a basic digestion followed by Fenton reactions. MPs were finally recovered and quantified using a stereomicroscope. 

An average of 17 MPs/g was found in the TMR. Most MPs were fibers of different colors (colorless, black, red and blue). The length ranged from 0.201 mm to 3.734 mm. 

In this trial we extracted for the first time MPs from dairy cows’ TMR and we verified the MPs presence in the animals diet. The incidence of MPs contaminations of TMRs and feeds (corn silage, hay and concentrate) is under investigation in different farms, as part of a larger project for the optimization of MPs extraction protocol of feeds and animal diets.

Abstract — The presence of microplastics in the forage and feedstuffs of domestic animals represents an imminent threat to the entire food chain that reaches humans as the particulates could pass the intestinal barriers contaminating blood and animal products. Until now, there is not a simple, quick, sustainable, and reliable method to detect microplastics in feeds. The objective of this work was to investigate the ability of Near-Infrared Spectroscopy to detect microplastics in ruminant feeds. Two types of instruments were tested using five feedstuffs (corn silage, mixed hay, rye grass silage, soy grain and total mixed ration). Two types of crumbled contaminants (low-density polyethylene and polystyrene) were accurately mixed at 0, 1, 3, and 5 mass mg g-1. The pool of the five matrices examined by the benchmark instrument (714-3333 nm) allowed an accuracy around 0.8 mg g-1 and a detection limit around 1 mg g-1 however, in separate calibrations, the errors could be halved. A short range of wavelength (714-1070 nm) or a smart NIRS instrument have prevented an acceptable discrimination of the concentrations. Following these preliminary results, any validation on other samples and with different and powerful NIRS tools is encouraged. 

Abstract - The contamination of microplastics (MPs) in the food-chain originates from feeds consumed by the livestock. The MPs present in crops, forages, and feeds, pass through the gut, and are partially absorbed or excreted with the faeces. MPs can be found in milk, meat and in the soil, where they return with the manure in a feed-animal-products-soil cycle. This widespread MPs presence needs the development of quick, simple, and reliable systems to verify their presence in the food-chain, starting from feeds. Until now very few studies have been conducted on the detection of MPs in feeds. Chemical extraction and Micro-Raman spectroscopy identification methods are the most used, but they are lengthy, expensive, laborious, and unsuitable for large-scale application. In this study, the ability of the Near-Infrared Spectroscopy to detect low-density polyethylene (LDPE) powder, added in different percentages (0, 0.05, 0.1, 0.3%; 0, 0.5, 1 and 3 mass mg g-1) to 10 different mixed hays, was investigated. Mixed hays were dried at 60°C and ground with a 2 mm sieve. The IdentiCheckTM FT-NIR-IR system (Perkin-Elmer), scanning in the 714-3333 nm range, with 2751 absorbance points, was used. Each absorbance spectrum was the average of 26 scans and each sample was mixed up and replicated 10 times. The direct scan of raw hays can detect LDPE up to 0.05% (~0.5 g kg-1) with a 0.02 mg g-1accuracy (R2=0.98). The different hays were also correctly identified (R2=0.91). Based on these preliminary results, any validation on other solid samples (feeds, products, faeces) is encouraged.

Abstract - Microplastics (MPs) are emerging environmental pollutants responsible for interconnected risks to environmental, human, and animal health. The livestock sector is highly affected by this issue, in fact MPs presence was recently detected in sheep faeces; follicular fluid, blood, milk and meat of cows. The MPs contamination in ruminants could be due to the intensive usage of plastic materials in farms. The main ones are silage bags, bale wraps, and plastic bunker silo covers made mainly in low-density polyethylene (LDPE). Although feeds might be the main source of MPs for ruminants, and consequently for their production chain, very little work has been conducted on them. Therefore, the aim of this work was to investigate the MPs contamination in three feeds highly used in livestock farms: corn silage, hay, and high protein feedstuff. Feed samples were collected in a farm located in N-W Italy, dried at 60°C overnight and grounded with a mill (5mm sieve).  The MPs extraction was done using a protocol specifically optimized to extract five MP polymers from feeds: low- and high-density polyethylene (LDPE, HDPE), polyamide (PA), polyethylene terephthalate (PET) and polystyrene (PS). The protocol involved three steps: 1. basic digestion, 2. Fenton reactions, 3. recovering and quantification of MPs. MPs were found in all the feeds analysed: 13.3±3.21 MPs/g of corn silage, 39.3±7.02 MPs/g of hay and 8.3±3.51 MPs/g of high protein feedstuff. This study is part of a project that has the aim to detect MPs in ruminant diets and feeds of different farms.

In "AGRIFOODPLAST" International Conference on Micro and Nano-Plastics in the Agri-Food Chain. Piacenza, Italy. September 10-12/2023.

Conclusion- The results of this study show that the homogenization of the samples does not eliminate the differences between the different types of burgers, so that they can be distinguished. In some way it is possible to evaluate the sensations that the chewing of a product transmits to the consumer upon consumption. Furthermore, this method can be used to analyse products that, due to their characteristics, are not suitable for classical TPA.

Conclusion- NIRS studies and applications on the vegan and meat burger discrimination are lacking. The present work confirms previous findings on Halal and game meat, highlighting that a NIRS optic instrument can accurately distinguish a vegan burger from a meaty one when the samples were previously proceeded with homogenization and freeze-dry. In fact, on a burger as-is it was not possible to reach an acceptable accuracy due to the complex and coarse structure.

Abstract - Plant-based burger (PBB) are food products that are designed to have meat-like characteristics, but do not contain any animal-derived ingredients. However, the sensorial experience of PBB complains about their lack of juiciness. Many analytical techniques, established for meat juiciness evaluation, would not seem to be sufficient to characterize meat and plant-based burgers. The objective of this study is to quantify PBB’s juiciness by novel techniques to follow the measurement of water/fluid in the burger from the original frozen/fresh status to the final cooked one i.e., what the consumer perceives in his mouth.

The study was performed on one meat (MT), two commercial PB (CE, CB) and 6 different prototypes of PB for a total of 80 burgers. CE was a pre-cooked PBB. Data were analyzed by GLM.

A functional protocol to be applied to meat and PBB was implemented to increase efficiency, to reduce cost and, to improve eating quality. 

The protocol is organised in modules, and therefore is possible to do some analyses instead of detecting more than 30 parameters obtained by applying the full version. The required instrumentations are the classic one found in a normal laboratory. Two instruments were used: the MCS instrument and the WHCtrend instrument which allow certain parameters to be measured semi-automatically. All percentages are expressed on the wet basis (%WB) to provide a correct comparison of the obtained values. 

Analyses are performed using the burger, first raw and then cooked, in its original, homogenised, and freeze-dried form. The following parameters can be detected: total moisture content (TMC), thawing loss, shrinkage (MCS), free water and water holding capacity, total fat and fluid cooking loss, water cooking loss, fluid to the mouth (FTM), fat loss, cooked specific fluid content per volume (CSFC), raw specific fluid content per volume, cooked specific fluid content per weigh. 

TMC for MT was 71.0% significantly greater than PBB (+9.6%); FTM was 47.6% like PBB but MCS was 23.8% significantly greater than PBB (+10.9%). So, meat retains more water than PBBs with a CSFC of 0.84 mg/mm3significantly greater than PBB (+0.222 mg/mm3).

Other parameters can be measured on the residual homogenate (cooked and raw) for a more detailed analysis of the characteristics of the burgers.

In conclusion, the methods employed to quantify meat juiciness were modified to make those methods suitable to also evaluate juiciness of PBB.

Abstract - Ankom DaisyII incubator (Ankom Technology, Macedon NY, USA) has gained acceptance as an alternative to traditional in vitro procedures to measure feed degradability. It reduces labour requirements and increases the number of determinations that can be completed by a single operator. The apparatus allows simultaneous incubation of multiple feedstuffs in the same jar, weighed in single bags, and placed in a continuously rotating incubator at 39.5 °C with a buffered inoculum. This simple procedure shows some functional limitation that can be resolved to obtain more reliable results. In particular, the jars do not rotate smoothly, with slowdowns, stops, and restarts that increase the variability of the instrument itself. In this paper, some low-cost and easily implementable structural adjustments are proposed, modifying the two drive rollers, and using a new drive pulley. These modifications can ensure steady conditions which are necessary in scientific experiments and reduce the doubts of the variability indegradability results related to an inaccurate instrumentation functionality.

Abstract - Texture profile analysis (TPA) is largely used to characterize semisolid foods. However, a recent study has verified that it cannot be recognized as a coherent method. So different alternatives were proposed. The objective of this study was to use the TPA on cooked burgers after homogenization (TPAH) and verify its relationship with fatty acid content (FA). Sixteen different types (48 samples: a meat and 15 plant-based burgers) were cooked at 165°C until 72°C to the core, homogenized in a grinder at 600rpm for 20s and placed in a 16 mL container. The compression extrudes the product up by a double compression cycle test, performed with a cylinder probe of 11.2mm diameter. Textural properties, including hardness, gumminess, chewiness, springiness, and adhesiveness were measured with an Instron 5543. On the same samples FA profile was analysed with a GC- 2010Plus (Shimadzu) after freeze-drying to maintain the nutritional characteristics. Statistical analysis applied the procedures GLM, simple and Canonical Correlation to describe the relationships between TPAH and FA of meat and plant-based burgers. Results showed that unsaturated FAs significantly affected the texture of burgers. Higher values of polyunsaturated FAs significantly reduced the hardness, gumminess, and chewiness. In addition, effect of monounsaturated FAs significantly reduced adhesiveness. Significant negative correlations were found between: oleic acid and adhesiveness (r=-0.43); linoleic acid and gumminess (r=-0.37) and chewiness (r=-0.35). Saturated FAs did not significantly affect the texture; however, some significant negative correlations were observed between lauric and miristic acids with hardness, gumminess, chewiness and positive with adhesiveness. Palmitic and stearic acids had a similar influence on hardness, gumminess, chewiness (positive correlation) and adhesiveness (negative correlation). It can be concluded that TPAH is correlated with FA composition (Figure 1) and polyunsaturated FAs can improve the burgers texture. Figure 1. Correlation between the TPAH and FA first canonical variable (CV) of cooked meat and plant-based burgers (MB = meat burger; the others all plant-based burgers)