Influence of milk-clotting enzymes of animal and microbial origin on the quality and shelf life of soft cheeses

A comparative test was carried out for milk-clotting enzymes (MCE) of animal origin (Naturen® Extra), microbial origin (Marzyme®) and MCE based on recombinant camel chymosin (Chy-max® M) in the production of soft cheese “Lyubitelskiy”. By the end of the shelf life of the cheeses (12 days at a temperature of 3 ± 1 °C), differences were noted in the degree of proteolysis (DP) and the value of the complex modulus G*, which were the following ones for cheeses produced with MCE of the brands: Naturen® — DP = 17.86 ± 0.24%; G* = 4164 ± 587 Pa; Marzyme® — DP = 17.98 ± 0.49%; G* = 4581±786 Pa; Chy-max® M — DP = 9.85 ± 0.63%; G* = 7949 ± 1157 Pa. Cheeses made with Chy-max® M MCE had a denser texture than cheeses made with MCE of Naturen or Marzyme, which did not differ significantly in consistency. In the studied cheeses, the severity of the bitter taste was proportional to the content of water-soluble peptides with a mass of 0.5–3 kDa. Cheeses with Marzyme® MCE had a more intense bitterness than cheeses with Naturen® MCE. There was no bitter taste in cheeses produced with MCE of Chy-max® M. It was concluded that in the production of soft cheeses, recombinant camel chymosin can be used to increase the shelf life, and MCE of microbial origin can be recommended to replace more expensive MCE of animal origin.

Ozone to Overcome Aspergillus flavus and Aflatoxin in Grains: Opportunities and Challenges of Implementation

<p>Ozone can be used as an alternative to control mold and aflatoxins in grains that is more eco-friendly because it does not leave residues that are harmful for humans, animals and environment. The use of ozone was quite effective in reducing mold and aflatoxin in grains such as barley, whole wheat, corn and rice. In Indonesia, ozone was limited used for sterilization of fruit and vegetable. Therefore, the comprehensive review on the potential of ozone in grains is needed, especially on the priority commodities of agricultural development in Indonesia, such as rice and corn. The objective of this review was to examine the opportunities of ozone to reduce Aspergillus flavus and aflatoxin in grains, so that it can improve its quality and shelf life. Many studies showed that the use of ozone reduced Aspergillus flavus and aflatoxin in grains by 50-90%.<br />Keywords: Grains, Aspergillus flavus, aflatoxin, ozone</p><p> </p><p><strong>Abstrak</strong></p><p><strong>OZON UNTUK MENGATASI CEMARAN ASPERGILLUS FLAVUS DAN</strong><br /><strong>AFLATOKSIN PADA BIJI-BIJIAN: PELUANG DAN TANTANGAN</strong><br /><strong>IMPLEMENTASI</strong></p><p>Ozon dapat digunakan sebagai salah satu alternatif pengendalian cendawan dan aflatoksin pada biji-bijian yang lebih ramah lingkungan karena tidak meninggalkan residu yang berbahaya bagi manusia, hewan, maupun lingkungan. Penggunaan ozon cukup efektif mengurangi kontaminasi cendawan dan aflatoksin pada bijibijian seperti barley, biji gandum, jagung, dan beras. Di Indonesia, ozon digunakan secara terbatas untuk proses pencucian beberapa jenis buah dan sayuran. Oleh karena itu diperlukan telaah lebih lanjut mengenai potensi penggunaan ozon pada biji-bijian terutama komoditas strategis yang menjadi prioritas dalam pembangunan pertanian di Indonesia seperti padi dan jagung. Tujuan dari tulisan ini adalah untuk menelaah peluang penggunaan ozon dalam mengurangi kontaminasi Aspergillus flavus dan cemaran aflatoksin pada produk biji-bijian, sehingga diharapkan dapat memperbaiki kualitas dan meningkatkan umur simpan produk. Hasil penelitian menunjukkan penggunaan ozon dapat menurunkan cemaran A. flavus dan aflatoksin pada biji-bijian sampai 50-90%.<br />Kata kunci: Biji-bijian, Aspergillus flavus, aflatoksin, ozon</p>

Recent Advances in the Mechanisms and Regulation of QS in Dairy Spoilage by Pseudomonas spp.

Food spoilage is a serious issue dramatically impacting the worldwide need to counteract food insecurity. Despite the very expensive application of low temperatures, the proper conservation of fresh dairy products is continuously threatened at different stages of production and commercialization by psychrotrophic populations mainly belonging to the Pseudomonas genus. These bacteria cause discolouration, loss of structure, and off-flavours, with fatal implications on the quality and shelf-life of products. While the effects of pseudomonad decay have been widely reported, the mechanisms responsible for the activation and regulation of spoilage pathways are still poorly explored. Recently, molecule signals and regulators involved in quorum sensing (QS), such as homoserine lactones, the luxR/luxI system, hdtS, and psoR, have been detected in spoiled products and bacterial spoiler species; this evidence suggests the role of bacterial cross talk in dairy spoilage and paves the way towards the search for novel preservation strategies based on QS inhibition. The aim of this review was to investigate the advancements achieved by the application of omic approaches in deciphering the molecular mechanisms controlled by QS systems in pseudomonads, by focusing on the regulators and metabolic pathways responsible for spoilage of fresh dairy products. In addition, due the ability of pseudomonads to quickly spread in the environment as biofilm communities, which may also include pathogenic and multidrug-resistant (MDR) species, the risk derived from the gaps in clearly defined and regulated sanitization actions is underlined.

Impact of Plasma-Activated Water Treatment on Quality and Shelf-Life of Fresh Spinach Leaves Evaluated by Comprehensive Metabolomic Analysis

Fresh baby spinach leaves are popular in salads and are sold as chilled and plastic-packed products. They are of high nutritional value but very perishable due to microbial contamination and enzymatic browning resulting from leaf senescence. Therefore, innovative food processing methods such as plasma-activated water (PAW) treatment are being explored regarding their applicability for ensuring food safety. PAW’s impact on food quality and shelf-life extension has, however, not been investigated extensively in vegetables so far. In the present study, a comprehensive metabolomic analysis was performed to determine possible changes in the metabolite contents of spinach leaves stored in a refrigerated state for eight days. Liquid chromatography high-resolution mass spectrometry, followed by stringent biostatistics, was used to compare the metabolomes in control, tap-water-rinsed or PAW-rinsed samples. No significant differences were discernible between the treatment groups at the beginning or end of the storage period. The observed loss of nutrients and activation of catabolic pathways were characteristic of a transition into the senescent state. Nonetheless, the presence of several polyphenolic antioxidants and γ-linolenic acid in the PAW-treated leaves indicated a significant increase in stress resistance and health-promoting antioxidant capacity in the sample. Furthermore, the enhancement of carbohydrate-related metabolisms indicated a delay in the senescence development. These findings demonstrated the potential of PAW to benefit food quality and the shelf-life of fresh spinach leaves.