Pseudomonas spp. and Enterobacteriaceae are dominant spoilage bacteria in chicken during cold storage (0°C-4°C). In this study, high resolution spectra in the range of 900-1700 nm were acquired and preprocessed using Savitzky-Golay convolution smoothing (SGCS), standard normal variate (SNV) and multiplicative scatter correction (MSC), respectively, and then mined using partial least squares (PLS) algorithm to relate to the total counts of Pseudomonas spp. and Enterobacteriaceae (PEC) of fresh chicken breasts to predict PEC rapidly. The results showed that with full 900-1700 nm range wavelength, MSC-PLS model built with MSC spectra performed better than PLS models with other spectra (RAW-PLS, SGCS-PLS, SNV-PLS), with correlation coefficient (R P ) of 0.954, root mean square error of prediction (RMSEP) of 0.396 log 10 CFU/g and residual predictive deviation (RPD) of 3.33 in prediction set. Based on the 12 optimal wavelengths (902

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Total viable count (TVC) is often used as an important indicator for chicken freshness evaluation. In this study, 112 fresh chicken flesh samples were acquired after slaughtered and their hyperspectral images were collected in the LW-NIR (900-1700 nm) range. The full LW-NIR spectra (486 wavebands) within the images were extracted and applied to related to reference TVC values measured in different storage periods, using partial least squares regression (PLSR) algorithm, resulting in high correlation coefficients (R) and low root mean square errors (RMSE), for either raw spectra or pretreatment spectra. By using regression coefficients (RC) method, 20, 18, 17 and 20 optimal wavebands were respectively selected from raw spectra, baseline correction (BC) spectra, Savitzky-Golay convolution smoothing (SGCS) spectra and standard normal variate (SNV) spectra and applied for the optimization of original full waveband PLSR model. By comparison, RC-PLSR model based on the SGCS spectra showed a better performance in TVC prediction with R C of 0.98 and RMSEC of 0.35 log 10 CFU/g in calibration set, and R P of 0.98 and RMSEP of 0.44 log 10 CFU/g in prediction set. At last, by transferring the best RC-PLSR model, the dynamic TVC change during the storage was visualized by color maps to indicate the TVC spoilage degree. The overall study revealed that LW-NIR hyperspectral imaging combined with PLSR could be used to predict the freshness of chicken flesh.

Accurate and rapid determination of nitrite contents is an important step for guaranteeing sausage quality. This study attempted to mine hyperspectral data in the range of 900-1700 nm for non-destructive and rapid prediction of nitrite contents in sausages. The average spectra of 156 samples were collected to relate to the measured nitrite values by partial least squares (PLS) regression. Optimal wavelengths were respectively selected by successive projections algorithm (SPA) and regression coefficients (RC) to simplify the PLS model. The results indicated that PLS model established with 15 optimal wavelengths (900.5 nm,

BACKGROUND Fusarium head blight (FHB) is one of the disasters that seriously harm wheat and other small grain crops. It causes spoilage and mildew of the grain leading to a significant decline in the yield and quality of the grain. This research aimed to isolate antagonistic bacteria to purify antifungal proteins. A strain was isolated from the rhizosphere of healthy wheat in a wheat field affected by a severe FHB epidemic. This isolated strain was tentatively identified as Paenibacillus polymyxa 7F1, which displayed a strong inhibitory effect against several other pathogens. One novel antifungal protein was purified from the P. polymyxa 7F1 and successfully expressed. RESULTS A crude culture of P. polymyxa 7F1 demonstrated antifungal activity that was stable at a temperature range of 60–90 °C and a pH range of 2.6–9.0. However, the antifungal activity of the P. polymyxa 7F1 was inhibited with proteinase K, trypsin, and neutral protease treatment. A 36 kDa protein with broad‐spectrum antifungal activity was purified from the P. polymyxa 7F1. A glycosyl hydrolase domain was identified from this protein through liquid chromatography–mass spectrometry (LC–MS) analysis. A recombinant plasmid pET32a(+)/36kd for prokaryotic expression was constructed, and the renatured p36kd protein demonstrated similar antifungal activity to the 36 kDa protein purified from the P. polymyxa 7F1. CONCLUSION A novel antifungal protein produced by P. polymyxa 7F1 was purified and expressed. The recombinant protein showed good antifungal activity as the novel purified protein. The novel antifungal protein provides an effective way to control the Fusarium head blight. © 2020 Society of Chemical Industry